I was picking up the new X3 yesterday and the old Service Manager was back helping out as one of their staff is away (he was promoted
). Had a chat to him and he's going to test drove with me. He said as it is in every gear in the same rev range at the same load, it is more than likely to be the exhaust. He is going to loosen everything up, run the car and re tighten everything to see if it solves the problem as that often does. I will keep you guys posted.