Turbo size

[IndyNova]

Hey guys, I have a 6.0 block with stock bottom end w/arp head studs, 317 aluminum heads with .600 patriot springs, .051 mls head gaskets, and ls6 intake and throttle body. I want to run 10-12 psi of boost, this will be a semi dual purpose car as is will be mostly street driven with some drag and autocross racing. I'd like to eventually go to a twin turbo setup, but am going with single for now. What size should I be looking at getting? Any help or advise will be much appreciated. Thanks