I generally use Red Line or Amsoil ATF in auto boxes, and frankly, don't trust the Audi manual's specificed 45k change interval for ATF on the A4.... 30k is more like it. Has anyone used a good synthetic ATF in the Tiptronic (Mobil 1, Red Line, Amsoil?). Red Line made a big difference in my C280 and I'm inclined to put it in the Avant after about 6,000 miles... <p>TIA...