well, the cars ive had, with cam work, eg mk6 fiesta 1.6 had a de cat, piper cams and full pipers exhaust and de cat.. was better throw the revs also my old saxo vts... cars do need back pressure, turbo cars dont, id say leave the cat alone, but others may say differnt.. its a 100 cell sport cat so cant really see any bhp up grades... but head work would mate..
