But now, I'm in again, and no more selling

Anyway, King Tiger is soon on it's way. Nicely used indoore , box stock. So I'm wondering what would the first best upgrades be ?
I'm thinking:
schumo idler , the KT0014AL kit
lower hull brace for tranny
turret roller
next would be
axel support of some sort
gear reduction
motors
Wich Graupner motor (ore other brand) will fit best , and run best is it the 480 ore the 400 motor ?
So why not Metal belt's you say . Well I probably going to buy a 'half built new in box missing only a few parts' KT later on wich comes with metal belts.
Ok thanks for watching.