Changed the oil last night on my father's 2.8 30v Audi A6. The oil that was in there was GC, and miles on oil was approx 11,030. Total makeup was about 1-3/4 quarts, not bad for this engine and OCI. I changed out the oil with Mobil 1 0w40. Let me tell you, maybe it's a placebo effect, but the 0w40 is a lot more responsive than the GC. Seems to have more pickup when I floor the car, and going from 65-80 takes a lot less time. Perhaps its the air temp or whatnot, but the 0w40 definatle feels better by use of the ol' butt-dyno. The 0w40 is just as quiet as the GC, definately not noisier. I'll have to see what effect the 0w40 has on gas milage compared to GC. I will also update you guys on consumption compared to GC. After testing Mobil 0w40 for 10k miles, I plan to try SUV 5w40. I will be sending in the sample of the GC to Blackstone either today or tomorrow, and will post results as soon as I get it, along with the TBN. I did use some Redline fuel system cleaner in the latter 1/3 of the OCI, but only maintenence doses; we'll see how much if any it affects the UOA.