I've got a couple of noises from the exhaust, and cannot figure out what it could be. The fist is a whistling noise, which I have been told it's normal on a turbo, with the windows down you can hear it but you cannot with them up. It also only happens when the revs are above 2000. The second noise is what I can only describe as if the the exhaust is blowing, I've checked the system this evening and I cannot find any holes, and it's just had a new flexi section which was a genuine part. now I do believe that the cat is on it's way out it's an 1996 A4 1.8T, so 14 years old with 119K on the clock and I know it's still on the original cat, mid section & back section. The car is not down on power and is running fine, there are no fault codes on the engine.