i have just purchased a greddy tt kit and i was wondering how much boost i could run on the stock bottom end? i have upgraded to 660cc. injectors to support the turbo but i am scared to go above 8 psi.! to go above that am i going to have to get the bottom end rebuilt?

well technically you dont HAVE to get it rebuilt...but if you want to go above 8 psi with stock internals you are taking a risk of blowing some stuff up...check out the AEBS 4.3 liter stroker kit...with this kit you should be able to handle all the boost you want

Not knowing your current mods, your main concern lies in the rods, pistons, and clutch. I am having my TT kit installed within the next week (3 phases). The first is just the kit w/ intercooler with turbo timer. The second involves the profec e01, clutch, and gauges. Finally, to top it all off (approx in one year) I'll change out the pistons (8.5:1) and rods (ours suck). I want to be able to push 12psi without worrying about the internals. Until then, I'll be happy with the newfound boost :D

350 with 12psi would be a rocket. Go for it, man.

660 injectors . . . yikes! You may want to investigate some fuel pump & pressure regulator options. 660 is quite larger, but our factory fuel system manages to drop fuel pressure like a mofo in the upper RPMs. There's a company that just released upgraded fuel components (fuel rails, etc), but I forgot who.