your boost creap is because you gutted the cat and i bet it doesnt go right atall when i took the cat off mine it feels like it was holding back and just hit fuel cut got to get it set up now on the 17th of next month i been told u can damage your motor like that and mine sounded like a tracktor when the mani to turbo gasket was crap as it was so thin the guy at the garage said the bolts wasnt clamping down tight enof