keep the gtst the RB25DET is a really strong motor if you want to make 340rwkw just rebuild the motor with forgies and stuff and upgade the turbo and got your self an aftermarket ECU it will cost you around the 8-10k mark and you will make that power easy if you go for the RB30 bottom end you will easy make 400-450 rwkw.
i may have my facts wrong here but from wat i have herd thats all
plus keep it rear wheel drive and upgrade the diff and drive shaft as you might blow the diff also the RB30 bottom end from what i have herd isnt really reliable again i may be wrong.
if you are having problems with getting the power to the road change your suspension make the rear shocks softer if you have adjustables there will be a sweet spot that works for you with your current set up. i know they look cool low and bouncy but its f**ks the sub frame and also they handel like a dogs balls.
and as frink said feed the power just dont plant it. this can also f**k ya motor and cause knocking as they are very strong they still need to be looked after.
hope this helps
