turbo question

well I got them for 400 (200 each)they only have dyno time on them and look brand new. I can send them in to garrett to be rebuilt if needed. my couzin has a really close friend that works for garrett. And he said he would rebuild them. So if they end up being junk I'll do that. But there is no shaft play in them and they spin freely by hand. They seem to be fine when I looked at them. I'm only going to run 7psi for now. Because the stock bottom end can't handle more than that. I have a 214/214 duration cam with about .556 lift (at the valve) on a 112 lsa installed on an icl of 105. The factory heads have been ported and polished. Compression is 9.6. And the motor makes 370 to the wheels in a ram. With about 25% driveline loss. So I figure I'm close to 460 flywheel. So even at 7 psi if I can net 50% power increase (assuming the ruel of thumb that 14 psi doubles power output) that should put me at 690 or so. (hopeing to see 650 to 700) does this sound reasonable or am I far off?