Ok Gang, I have not kept up on the threads on lubricants, but what is the hot tip for the S4/200TQ Trans? Is the new Castrol Synthetic or Mobil 1 the way to go? Manual says synthetic, but what is that? Does the GL-5 rating apply? Thanks Paul Rivera 83 Ur-Q 91 200 TQW 93 S4 94 S4 (take delivery on Friday God Willing)