How fast do you wanna go - really
and how far do you wanna go - really
as its a v3 you can break into 20rps easily with nearly all stock internal box
then just rewire, fet, deans etc... on stock gears - fir shs or other beefy neodym motor
test it all out if she is good with motor connectors, then cut n solder for extra boost
wire in fet etc with dedicated wires motor to battery - neg to fet to battery
then the positive switch wires on their own thinner wiring.
All this equals next to no join or resistance points for max power flow to motor
(often speed freaks will forgo any fuse but only if you have common sense and know your gun)
inside the box just cheap service like AOE, new piston ring, o-ring nozzle, ptfe tape on head
or new cylinder head if you wish and bearing spring guide perhaps
You do not need to replace everything inside box - std piston & gears will be fine for a decent upgrade
More higher rof will require more work and crap out quicker with more additional problems
eg: Pre Engagement, double cycle/firing, feeding problems at higher speeds etc etc etc.......
for easier life and less stress stick to a reasonable upgrade - service the box & rewire with fet
then drop in a decent neodym motor - that is where you should spend £30 on
inside the box maybe £20 or so but no more than £25-£30 really
then spend about £20 for basic £10 fet, decent wire & some deans etc....
Not a massive amount but with motor, service box and mosfet it is about £70 still
people buy loads of bits n bobs - hi speed gears and lonex steel pistons n heads etc...
but as long as seals are good stock stuff is fine for most people
sure if you are shortstroking you want more steel teeth to remove
But you don't need to go nutz inside the box either
get the aoe and seals done, shim it as best as you possibly can
grease it where needed, nozzle n spring guide - box done
fit the mosfet if possible if funds allow - leave motor until next month
gun is sorted and motor drop in as n when you got the dosh
keep her 20 to 25rps or you will have more stuff to do
The most you should spend is time