i ran 16-17 psi on mine but had a chip/rom made up. Fatsport used to be able to make up chip/rom, not sure anymore and Verso will be able to soon i am pritty sure.

There is a odd shaped resonator thingo after the AFM take that out and get a replacement pipe.

Go to
http://www.rslibertyclub.org/forums/ helped me a lot when i had my old wrx