Have to get in a little dig at my friends over at Redline Oil .... The quarts of their 5w-20 synthetic at Advance Auto are only labelled ACEA "A1/B1" - surely it meets the long drain, A5/B5 spec like Mobil 1? The quarts of 5w-30/10w-30/10w-40/20w-50 are all labelled ACEA "A5/B5", which requires a high temp, high shear viscosity < 3.5 Centipoise @ 150C. Redlines own data shows all these viscosities have HT/HS > 3.5 Cp @ 150C. So these should all be labelled ACEA A3/B3, if not A3/B4. To be fair, I did pick up some of their excellent "SL-1" fuel injector cleaner and a bottle of "Waterwetter" to play around with. Maybe someone can tell me if the WW is compatable with the G-12 coolant in the Audi TT? I can't remember if that's an "OAT" or "HOAT" type formulation?