With my MY00 car I have recently experienced overboosting in 4th and 5th gears wherby you floor the pedal in one of these gears and sometimes in 3rd with low rpm and the turbo boosts to 1.3 and tails back and repetadly does this providing very jerky acceleration. My car has full S/S exhaust system and a Blitz Induction with Prodrive Intercooler piping. The problem only started with the addition of the center de-cat section ... can anyone help ?

I was wondering if there was a problem with a lack of back pressure now with the free flow system.