hey
welcome to the forum
6-7psi is good for stock and worn engine
to boost 10-12 psi all you need is a boost controller and you should be fine... just make sure you engine is well looked after and not due to blow it's head gasket anytime soon hehe
i have made this thread in FAQ that you might want to read to save me writing it all again :P
http://www.toyota-supra.info/forums/index....act=ST&f=2&t=53
lemme know if you need any further information etc and i'd be happy to help