i had some issues with my r33 gts-t when i brought it....it was lagging power when on boost
took it to a trusty mechanic and he told me my catalyic converter was glogged up with shit....so he knocked it out
after that man good as gold...had a tune and some more boost.... and the result was 190.1kw @ 9psi and the wheels stock as a rock besides spitfire coilpacks