hi i am waiting for audi to get me a new cat,as its on back order. my car (1.6fsi) started illuminating the eml(red engine manegment light) on the dash. so i had it scanned and it had catalist emisions failure logged. so had an auto electrician have a look when the engine was running just to pinpoint the fault. he showed me that the cat wasn't getting up to temp so the ecu was switching the heater element on and off to try and get it hot.along with looking at other sensors he said my cat had failed. probably due to the first owner only doing short trips and doing only 20,000 miles in 4 years. the other problems i was getting were a flat bottom end (under 3000rpm)plus a slight rattle to the cat if you blipped the throttle. audi say the cat is £275 plus vat. i was advised not to get a pattern part as they can be suspect quality and life expectancy can be short. i dont plan on selling it so am going audi part. good luck mike