You can start researching as soon as you place a research facility. The higher your research building level the more can research + a higher lvl also increases the research speed and amount of things you can research. To unlock Research facility lvl 22 you will need almost all other buildings in your base. This makes a lot of researches double, from a maximum of 10 to max of 20. For all building stats, look here.
What research should you do? It depends. If you want to be the biggest attacker out there and be a huge rally leader, you will have to put the time and money. Because apart from the first trees, it’s gonna cost you some serious money especially when new stuff comes out. If you have all research done you’re ‘Max Research’, until new research comes out that is. You can still enjoy the game without spending a lot of money. If you’re a trap you’ll want to limit your research so your base is not too big in power and people will want to rally it.
Required for doing research:
  1. Research facility
  2. RSS to do research (sometimes a tree becomes free of rss)
  3. Speeds (unless you’re willing to wait years)
  4. Research Files, normal ones and special files
  5. Research Gear & skill tree (well not required but highly recommended)
  6. Some advise a drink for tapping trough the difficult trees
To make the most out of researching use:

Research insignia‘s, research boosts, state boost, timing them with challenges, commander support, (needs someone in your alliance with comm at least lvl 64) and in some cases you can get a research tree free from rss by special boosts from MS or buying it in packs. Check if there is a research state open to make it all faster and cheaper. You’ll see that in the blog. Those states require special teleports, you can get in packs and/or challenges.

01.economyECONOMY

The first basic research, easy on rss and speeds. Tree needs to filled out, except gold gathering to unlock T4 troops in combat tree.

NEEDS: RSS & SPEEDS

  • Construction (up to +66%)
  • Rss Production (up to +78%)
  • Troop Load (up to +66%)
  • Deployment Speed (up to +66%)
  • Gathering (up to +66%)
  • Gold Gathering (up to +10%)

02.combatCOMBAT

The second basic research, easy on rss and speeds. This is where you unlock regular troops so you can train and use them. The higher the tier troop the more you will have to research in this tree.

NEEDS: RSS, SPEEDS, RESEARCH FILES, COMBAT RESTRICTED FILES

  • Scouting
  • Training Speed (+20%)
  • Specific Troop Attack (up to +300%)
  • Specific Troop Defence (up to +281%)
  • Unlocking regular T1, T2, T3 & T4 troops
  • Troop Health & Defence (up to +281%)
PART II Heavy on files and speeds

NEEDS: RSS, SPEEDS, RESEARCH FILES, FUTURE COMBAT RESTRICTED FILES

  • Unlock T5 Troops
  • Unlock T5 Traps
  • Resource Training Cost Reduction T5 troops (up to +30%)
  • Specific Elite Troop Defence (up to +1000%)
  • Specific Elite Troop Health (up to +1000%)
  • Specific Elite Troop Attack (up to +1000%)
  • Elite Trap Defence & Attack (up to +300%)
  • Death Row Elimination Duration (up to 1 day) Bonus Reward
  • Troop Attack With Commander (up to +1000%) Bonus Reward
  • Troop Health With Commander (up to +650%)
  • Troop Defence With Commander (up to +650%)
  • RSS Send & Receive Capacity III (up to +75m)
  • ?? (??)

03.trapsTRAP

The third basic research, easy on rss, speeds & files. This is where you unlock regular traps to fill your wall with.

NEEDS: RSS, SPEEDS, RESEARCH FILES, TRAP RESTRICTED FILES

  • Trap Building
  • Unlocking regular T1, T2, T3 & T4 traps
  • Trap Attack & Defence (up to +200%)

04.commanderCOMMANDER

The fourth basic research, not that hard on rss, speeds & files. This is where you unlock rebels so you can hit them and more.

NEEDS: RSS, SPEEDS, RESEARCH FILES, COMMANDER RESTRICTED FILES

  • Unlocking Rebel targets 1-9
  • Increasing Rebel Attacking & reducing energy needed
  • Commander Deployment Speed (up to 52.5%)
  • +1 Deployment Slot
  • Trap Attack & Defence (up to +200%)
  • Training Speed ll (+24%)
  • Hospital Healing Speed (+79%)
  • Troop Health & Defence (up to +65.8%)

05. advtroopsADVANCED COMBAT

The fifth research, basic for attackers and rally fillers, not always researched by traps. Not that hard on rss, speeds & files. This is where you unlock Advanced Troops so you can train and use them.

NEEDS: RSS, SPEEDS, RESEARCH FILES, ADVANCED COMBAT RESTRICTED FILES

  • Unlocking Advanced T1, T2, T3 & T4
  • Specific Advanced Troop Attack (up to +300%)
  • Specific Advanced Troop Defence (up to +300%)
  • Advanced Troop Defence & Health (up to +281%)
PART II Heavy on files and speeds, especially heavy on the normal research files

NEEDS: RSS, SPEEDS, RESEARCH FILES, FUTURE ADVANCED COMBAT RESTRICTED FILES

  • Unlock Advanced T5 Troops
  • Unlock Advanced T5 Traps
  • Resource Training Cost Reduction Advanced T5 troops (up to +30%)
  • Specific Elite Advanced Troop Defence (up to +1000%)
  • Specific Elite Advanced Troop Health (up to +1000%)
  • Specific Elite Advanced Troop Attack (up to +1000%)
  • All Rally Size Capacity Increase I (up to +2,15m)
  • Death Row Elimination Duration (up to 1 day)
  • Rally Defence (up to +2000%)
  • Rally Health (up to +2000%)
  • Control Point Troop Defence (up to +2000%)
  • Control Point Troop Health (up to +2000%)
  • Control Point Troop Attack (up to +2000%)
  • Attack Deployment Capacity Increase II (up to +600k)
  • Troop Attack With Commander II (up to +3000%)
  • Troop Health With Commander (up to +1000%)
  • Troop Defence With Commander (up to +750%)
  • All Rally Size Capacity Increase II (up to +2,65m)
  • Rally Attack Bonus (up to 2000%)
  • RSS Send & Receive Capacity III (up to +75m)
  • Increased Embassy Troop capacity (up to +750k)
  • ?? (??)

06. advtrapsADVANCED TRAP

The 6th research, still not hard on rss, speeds & files. This is where you unlock advanced traps to fill your wall with.

NEEDS: RSS, SPEEDS, RESEARCH FILES, ADVANCED TRAP RESTRICTED FILES

  • Unlocking advanced T1, T2, T3 & T4 traps
  • Advanced Trap Attack & Defence (up to +200%)

07. manufacturingMANUFACTURING

The 7th research, this is where its getting harder on rss, speeds & files. But easy compared to upcoming researches.

NEEDS: RSS, SPEEDS, RESEARCH FILES, MANUFACTURING RESTRICTED FILES

  • Unlocking Core Mastery level 1-6
  • Troop Load ll & Gathering ll (up to+66%)
  • Manufacturing Speed (up to +20%)
  • Unlocking 4th, 5th & 6th Attachments Core Gear
  • Unlocking 4th Mod Slot Core gear
  • Finding Core materials While gathering chance (up to +30%)
  • Core Gear Duration (up to 25%)
  • Finding Core Attachments While gathering chance (up to +30%)
  • Core Gear Manufacturing Luck (up to +20%)
  • Manufacturing Speed ll (up to +60%)
  • Manufacturing Coin Cost Reduction (up to +10%)
  • Unlocking 4th Mod Slot Normal Gear
  • Manufacturing Coin Cost Reduction ll (up to +15%)
  • Core Gear Duration (up to 36%)
  • Core Gear Manufacturing Luck (up to +60%)

08.battletacticsBATTLE TACTIC

If you thought the manufacturing tree was tough on rss, speeds & files then buckle up if you want to finish this tree.

NEEDS: A LOT OF RSS, SPEEDS, RESEARCH FILES, BATTE TACTIC RESTRICTED FILES

  • Gathering & Commander Deployment Speed (up to 40%)
  • Gathering lll (up to+40%)
  • Embassy Capacity Increase (up to +500k)
  • 4 Commander Presets
  • Attack Deployment Speed (up to +20%)
  • Deployment Slot ll (up to 2 slots)
  • Rally Time reduction (-1 min)
  • Troop Defence, Health, Attack lll (up to +60%)
  • Deployment & War Deployment Speed (up to +40%)
  • Rally Reinforcement & Rally Deployment Speed (up to +20%)
  • Rally Attack Bonus (up to +20%)
  • Rally Time Reduction ll (-1 min)
  • Specific Troop Defence lll (up to +300%)
  • Wall Trap Attack & Defence ll (up to 200%)
  • Wall Trap Capacity (up to +275k)
  • Gathering & Trade Deployment Speed ll (up to +20%) Bonus Reward
  • RSS Gathering Deployment Capacity (up to +50k)
  • Embassy Capacity Increase ll (up to +500k)
  • Embassy Defence Bonus ll (up to +25%)
  • Gathering V & Troop Load lll (up to +100%)
  • RSS Help Capacity Increase ll (up to +12m)
  • Specific Troop Health lll (up to +300%)
  • Attack & Commander Deployment Speed (up to +20%) Bonus Reward
  • Death Row Elimination Duration (up to +1 day)
  • Hospital Capacity ll (up to +250%) Bonus reward
  • Troop Queue (up to +500%)
  • Radar Station Attack Penalty ll (up to +25%)
  • Attack Deployment Capacity (up to +50k) Bonus Reward
  • Rally Reinforcement Speed ll (up to +20%) Bonus Reward
  • Rally Capacity Increase (up to +200k)
  • Rally Time Reduction IV (-1 min) Bonus Reward
  • Specific Troop Attack lll (up to +200%)
  • War Zone & Rally Deployment Speed ll (up to +20%) Bonus Reward
  • CP Rally Capacity Increase (up to +200k)
  • Troop Defence & Health with Commander (up to +400%)
  • Troop Attack with Commander (up to +300%) Bonus Reward
  • GCP Rally Capacity Increase (up to +200k)
  • Deployment Speed (?)

09.setbonusSET BONUS

Ever seen shiny gear sets on peoples commander? They did at least a bit of this research. Not cheap on rss and speeds, files needed are doable.

NEEDS: A LOT OF RSS, SPEEDS, RESEARCH FILES, SET BONUS RESTRICTED FILES

  • Unlock Base set (5) with Normal Gear (up to 20% per piece)
  • Unlock Base set (5) with Core Gear (up to 20% per piece)
  • Unlock Full set 2nd & 3rd accessory with Normal Gear (up to +50%)
  • Unlock Full set 2nd & 3rd accessory with Core Gear (up to +50%)
  • Specialised Commander Bonus (up to +100%) 
  • Specialised specific troop Defence (up to +100%)
  • Specialised specific troop Health (up to +100%)
  • Specialised specific troop Attack (up to +100%)
  • 3 Commander Presets
  • Specialised Troop Defence (up to +100%)
  • Specialised Troop Health (up to +100%)
  • Specialised Troop Attack (up to +100%)

10.modsetbonusMOD SET BONUS

Gives a boost to mod sets. The boost depends on the mod set you’re using. Not cheap on rss and speeds, files needed are doable.

NEEDS: A LOT OF RSS, SPEEDS, RESEARCH FILES, MOD SET BONUS RESTRICTED FILES

  • Mod Set Bonus Modifier (up to 25%)
  • Construction, Research, Rebel target, Training Mod Set Bonus (up to 200%)
  • Mod Set Bonus Modifier ll (up to 75%)
  • Specific Troop Attack Mod Set Bonus (up to +200%)
  • Deployment Speed lll & Gathering lV Mod Set Bonus (up to 100%)
  • 2 Commander Presets
  • Specific Troop Defence Mod Set Bonus (up to +200%)
  • Troop Defence Mod Set Bonus (up to +200%)
  • Deployment Speed & Gathering Mod Set Bonus (up to +200%)
  • Specific Troop Health Mod Set Bonus (up to +200%)
  • Troop Health Mod Set Bonus (up to +200%)
  • Troop Promotion & RSS production Mod Set Bonus (up to +200%)
  • Specific Troop Attack Mod Set Bonus (up to +200%)
  • Troop Attack Mod Set Bonus (up to +200%)
  • Rally Time Reduction lll (-1 min)
  • ?? (?)

11.building-developBUILDING DEVELOPMENT

Boosts your buildings and option to unlock second insignia. Buckle up on rss and speeds & files if you want to complete this tree.

NEEDS: A LOT OF RSS, SPEEDS, RESEARCH FILES, BUILDING DEVELOPMENT RESTRICTED FILES

  • RSS buildings Capacity and Production (up to 50% )
  • Warehouse Capacity (up to +5000%)
  • Trading Post Capacity (up to +8m)
  • Trade Post Help Tax Decrease (up to -1%)
  • Hall of Heroes XP modifier (up to +165%)
  • Wall Trap Attack & Defence (up to +200%)
  • Wall Trap Capacity (up to +275k)
  • Radar Station Attack Penalty (up to +25%)
  • Embassy Defence Bonus (up to +25%)
  • Hospital Healing Speed & Capacity (up to +200%)
  • Armory Core Duration (up to +10%)
  • Research Speed (up to +40%)
  • Unlock 2nd Insignia Slot
  • Vault Deposit Size & Interest Rate (up to +7%)
  • Troop Academy Promotion Capacity & Speed (up to +200%)
  • Combat Lab Efficiency (up to +10%)
  • Death Row Attack bonus (up to +250%)
  • Death Row Health bonus (up to +150%)
  • Death Row Defence bonus (up to +200%)
  • Prison Captured Commander Bonus (up to +200%)
  • Prison Bonus Multiple Commanders (up to +3)
  • Troop Defence V & Health IV (up to +300%)
  • Troop Attack IV (up to 500%)
  • ??? (?)

12.mercenaryMERCENARY COMBAT

To unlock the 3rd troop type. As you could have expected, not cheap on rss and speeds & files if you want to complete this tree.

NEEDS: A LOT OF RSS, SPEEDS, RESEARCH FILES, MERCENARY COMBAT RESTRICTED FILES

  • Unlock Mercenary T1, T2, T3 & T4 troops + Bonus Reward
  • Specific Troop Type Mercenary Attack (up to +300%)
  • Specific Troop Type Mercenary Defence (up to +281%)
  • Death Row Defence & Health Bonus ll (up to +200%)
  • Deployment Presets (up to 10) Bonus Reward
  • Specific Troop type Health & Defence Bonus all troops (up to +100%)
  • Mercenary Troop Defence & Health (up to +281%)
  • Death Row Attack Bonus ll (up to +300%)
  • Specific Troop type Attack Bonus all troops (up to +100%)
  • Troop Defence VI & Health VI (up to +400%)
  • Troop Attack V (up to +600%) Bonus Reward

13.augmentAUGMENTS

To unlock augments and be able to put them on your weapon. Very heavy on Speeds, I am not joking

NEEDS: A LOT OF RSS, SPEEDS, RESEARCH FILES, AUGMENT RESTRICTED FILES

  • Unlock Augment Slot 1 Normal Weapon
  • Unlock Augment Slot 1 Core Weapon
  • Specific Troop Type Defence with Commander (up to +325%)
  • Unlock Augment Slot 2 Normal Weapon
  • Unlock Augment Slot 2 Core Weapon
  • Commander Promotion Queue (up to +20%)
  • Specific Troop Type Health with Commander (up to +325%) Bonus Reward
  • Unlock Augment Slot 3 Normal Weapon
  • Unlock Augment Slot 3 Core Weapon
  • Commander Training Queue (up to +20%)
  • Specific Troop Type Attack with Commander (up to +325%) Bonus Reward
  • Unlock Augment Slot 4 Normal Weapon
  • Unlock Augment Slot 4 Core Weapon
  • Core Manufacturing Luck ll (up to +20%)
  • Normal & Core Gear Manufacturing Cost reduction & Speed (up to +20%)
  • Augment Multiplier Slot 1 Normal Weapon (up to +500%) Bonus Reward
  • Augment Multiplier Slot 1 Core Weapon (up to +500%)
  • Core Gear Duration lll (up to +20%) Bonus Reward
  • Augment Multiplier Slot 2 Normal Weapon (up to +500%) 
  • Augment Multiplier Slot 2 Core Weapon (up to +500%)
  • Commander Critical Hit lll (up to +5%) Bonus Reward
  • Troop Defence & Health with Commander ll (up to +500%) Bonus Reward
  • Augment Multiplier Slot 3 Normal Weapon (up to +500%) Bonus Reward
  • Augment Multiplier Slot 3 Core Weapon (up to +500%)
  • Commander Energy Recovery (up to +20%) Bonus Reward
  • Augment Multiplier Slot 4 Normal Weapon (up to +500%) 
  • Augment Multiplier Slot 4 Core Weapon (up to +500%)
  • Commander Attack lll (up to +20%) Bonus Reward
  • Troop Attack with Commander ll (up to +500%) Bonus Reward
To Be Continued..
These are all the research trees so far, but expect many more and some trees to become longer. No need to get mad about it, or get frustrated that’s just how the game works. If you want a certain new research fast, it’s gonna cost you a lot of packs. In time every tree gets less hard, because the packs get better. You don’t need all this research to have fun with this game.