I'm in a 2.4 and have been quoted £400 for a cat back 2.5" stainless steel. The 2.4's a twin exhaust, but he said, if it were a single exhaust he could probably do it for around the £275 mark. So find yourself a decent local custom exhaust place, get it up on a ramp so they can have a look and get a quote. Took my guy less than 5 minutes to give me a quote and I'll definitely be taking him up on it later in the year (especially when I saw some of the other cars he was working on :wub: ).