Hey guys,
I have a fairly mechanically standard GSR from my knowledge and the guy that had it before me put in a higher boost switch which makes it run on 20psi. I run it on that most of the time with no problems.
TD04L, standard injectos (390cc), standard exhaust manifold, dump pipe, intercooler. It does however have an aftermarket no brand BOV. The only issue on 20psi is the fuel economy! I should take it apart to see the internals but have not yet had the time.
Cheers