I have an f20b with stock internals. I have a gt35 ball bearing turbo set up and I was told running it stock I could run 12 psi no problem. What's everyone's opinions?

 

With a well designed setup, and a GOOD TUNE you should be fine.

Personally, I would say a GT35 will be fairly laggy on a 2 liter engine, and won't really be able to run very efficiently in it's best range. That is a 400+ HP turbo generally.