Cyma m14 parts list

Hello people
my cyma 032 has been acting up lately, when firing on semi the power starts very low (0.6j) and with each pull increases up to 1j and stabilises there, when you stop shooting for a bit it starts shooting weak again.
Reading a few posts here i've concluded it might be a hopup or compression issue and i've decided that if im going to open the gearbox im going to take the opportunity to upgrade it and i've come up with these parts until now:

Cut Off Lever For Gearbox Ver 7 (SHS)
Cylinder head for M14 (SHS)
M14 Nozzle(21.5mm) (SHS)
Maple Leaf 2021 Super Macaron Hop Up Silicone 60° for AEG (Yellow)
Maple Leaf HOP UP Tensioner nub Ω
Chihai Motor "Destruction of God" CHF-480WA-28TPA 19k Nd-Fe-B Ver.3 Gearbox M90-M120 High Torque
CNC Steel 13:1 gears (SHS) (can/should i keep existing v7 spur gear and replace the other two with these gears?)
VULPO Gear Set Gap Adjustment Shim Set
Gate NanoASR Mosfet

Am i missing something? i've only ever opened up v2 and v3 replicas so im a total newbie when it comes to v7
Please share your wisdom with me, all suggestions and tips are welcome!