1. Kit "Fix"
Fix all types of resistance.
Kits no longer provide over-armor 'bonus'.
Example:
original armor value>10
Current armor value>-8
Use +25 armor kit>New Current armor Value>10(+18 although kit used was +25)
Fix of Energy/Cooling Kit
Example potential stats for these kits will use the "Master Kit 7 version"

Master Cooling Kit
Adds a permanent +14 Heat regeneration. (Last for duration of battle?)
Subtracts 50 Heat instantly.

Master Energy Kit
Adds a permanent +14 Energy regeneration.(Last for duration of battle?)
Adds 50 Energy instantly.

2. Buff Core/Module (Takes a module slot or A new slot can be added for this All Items are of Legendary rarity)
Master Tank Module/Core>Adds Additional +100HP +5% overall damage reduction(Passive)
Adapting Armor Module/Core>Changes your armor to the damage type last used. Initially+15 in Physical(Conventional armor cannot be equipped if this is a module. If this is a core, then it will be the initial 15 that will be adapting and not the base conventional armor should it be equipped.Passive)
Fortifying Armor Module/Core>Increases armor by +1 for the last damage type used.
Invincibility Module/Core> Damage Reduction by 85% when under 5% of total Health.(Passive)
Power Module/Core> Increases damage of all types by 5% when equipped.(Passive)
Defense Module/Core>Repairs your Mech for 25 Hp every turn. (Consumes -25 energy when turned on. Active)
HypoRegeneration Module/Core>Provide +20 Energy AND Heat regen once Mech has either passed the overheat threshold or the 0 Energy Threshold.(Passive, Can activate a maximum of 2 times per battle)
Example for HypoRegeneration:
100 Base heat
50 Base Regen
Once your heat is 151/100 HypoRegen kicks in and you will cool down by 70 and adds 20 energy.
Final heat= 81/151
Energy Explanation:
Once your opponent has drained all your energy to 0, At the start of your next turn, Hypo Regen kicks in and adds 20 energy and cools you down for 20.

Insta-Thread bump.

1a) Resist kit - absolutely yes!!!
1b) Heat/energy kits - yes to the match long boost to regen/cooling but not combined with instant regen/cooling
2) I'm not a fan of creating a new slot for these items but as modules some could work
Tank Module - no, this is what armor modules are for and 100 hp is too high
Adapting Module - no if you mean this as basically an extra, all encompassing resist module
Fortifying Module - no, I think sky-high resists are generally a bad idea
Invincibility Module - I'm not decided on this one yet. Seems OP but if it takes up a module slot it might be workable
Power Module - I like this idea
Defense Module - This requires an action point to activate? If so, I like the idea. 25hp might be too much. Maybe make it more like 10 but interesting idea.
HypoRegen Module - I kinda like this one too.

All items can be balanced by weight If it takes it's own slot.

I prefer it be balanced by module slot and weight.

The Defense Module requires you to turn it on before it becomes active. Similar to Drone activation. It turns off once energy becomes drain and remains off. Similar to Shield activation.

Additional note on Fortifying module, It only add resistance to your loss resistance. If you had only 10 Resistance, It will not add you to 11.

I thought about the adapting module and lowered it to 15. The idea is to encourage multiple weapon types on a mechs.

Added Damage Resistance to Tank Module as I forgot to add that.