hi patto

in all the years of tuning rs turbos i have never had to change an auxillary air vavle as long as the m head is clean, you have clean oil brether pipes and the dipstick has not come out. all it will need most of the time is the base mixture setting as this is a mecanical system a can go out of tune very quikley the best thing to do is to have it all set up on a rolling road for the best resault.