I am thinking of installing a MBC ( manual boost control) and putting about 8.5 psi ( 8 - 10 HP / 1psi) . I know that it can wreck my engine, currently I have put about 6.5-8 lbs of boost with no problems. Factory settings are 7.5-8 psi, but not all were calibrated. Engine is stock, but stock engines handle about 12.5-13.8 psi without shut off valve engaging, so I would be well with in the limit and not exceed it . My turbo is a mistu TD04 and can put out up to 30psi, although that will definately blow your headgasket, as tested by someone else. I do plan to have a 3 inch cat back with a turbo muffler installed and have found one for about 350.