This is my list of parts to get to 400rwkw: GTX3582R + ported wastegate & flapper mod 4inch turbo side intake 1000cc injectors (I think your 80lbers will be ok) Surge tank + 044 Bigger Intercooler Valvesprings 4 inch dumppipe + high flow cat going into a 3.5 inch catback. Xcal3 Purely on engine mods, I spent close to $9000. Add to that the cost of fitting parts if you can't and tuning the car and that figure will be closer to $12,000 Don't forget that the G6ET does not come with a LSD. A decent tailshaft, LSD and diff bush combo will set you back about $3000. As for the gearbox, once you get to 400rwkw, start saving immediately for a ZF rebuild. It will need one eventually. As for the fuel system, if you really want 400rwkw, then budget for a surge tank + 044.