Not every car is the same...mine made only about 12-13 on a 3.2" with stock heads and pacesetters/3" exhaust...ported everything else.

My buddy's GTP saw 13-15psi on a 3.4" with PEM's and a 3" DP...even with the cutout open it still made 12...it just had a lot of boost...who knows...no codes and everything was fine.