de catted my 1.8 wen i had it. i made my own decat pipe from the old exhaust that was replaced with a piper cat back exhaust. was then fitted to my 2.0 which funny enough was takin off last nite and nw sittin doin nothin. sounds alrite, bit tinny for my likin and made no increase in power. brought the MIL light on which made the car run rough and carryin petrol to the beast was a nightmare. search ebay for obx 4-1 manifold for focus. it has a de-cat pipe as well as a free flowin top exhaust header! worth the money too.