if your goal is to be fast and have your car still running, you should upgrade the supporting mods BEFORE upgrading the turbo.

start with: 14b,fmic,walbro255,550's
skip the gm translator...it's just not necessary. get something to tune your car. safc and a data logger at a minimum. better yet, get an EMS or dsmlink.

it is a simple formula. air + fuel + spark = HP.

you have air w/ an intake and exhaust. you have NO fuel upgrades. The stock coils will spark far into the 300 - 400 hp range. you first need fuel and to cool down your air with a bigger intercooler. when you add fuel via bigger injectors and a wally, you will need a way to control fuel delivery at all points in the rpm range...hence the safc. your stock ecu just isn't going to handle 550s and a wally optimally.

then, look into a 16g.