In the coming days I shall be crawling under my car to examine the boost pipes. The reason for this is that I am sure I have some kind of boost leak because when accelerating there is a low pitch air escaping noise that also sounds a bit like a constant rubbing sound. Hard to describe. As well as this the car averages about 34mpg. My friends mk4 golf with same engine gets around 45mpg and his is nice and quiet. So I will be checking for anything loose etc. Also, I remeber when last under there