well, the block starts to experiance flex at 20lbs, which cracks stock caps, and i bet it will knock at less boost than that which can blow a head gasket, that is what i am worried about, i don't want to blow the back off of another motor. Last time i was running 23 lbs, i had no knock, but i blew the backhalf of the block off, and chucked the crank and the tranny bellhousing was in 34 peices. This was all because the block was flexing and it cracked a cap. You will make more power on a 45a at 16lbs than you will with a stocker with 16lbs, if you don't think so you are stupid. If my 51 feels like it makes less power than my stocker, i wouldn't be worried why some guy wants to buy a 45a and run 16lbs of boost.
Nicholas
As long as you have good gas and have no or little detonation you should be running at least 20 - 24lbs of boost with a 45a or 63-1. Those turbos aren't even getting close to there full potential until about 26 psi, so unless you like having a big turbo with lag I would suggest you get a smaller turbo like a TA-49 or TE-44 if your goals are only low 12's to high 11's. It makes no sense to run low 12's to high 11's with a 63-1 or 45a cause those are solid 10 second turbos that need ported heads, big fuel injectors, big stall converters and for a low 12 to high 11 second car you don't need all that stuff. Hell, there are guys on this BB running low 12's with the stock turbo, injectors, IC, and D5 converter so why would you want to spend all that $$$ to run low 12's 
