Hello everybody, Fantastic site! I've been lurking for a couple months now. I have a 2003 Audi A4 1.8T, which calls for ACEA A3 spec, preferably 0W30, but 5W30 is allowed. Before I found out what ACEA A3 was, I topped it off with 1/2 liter of Castrol GTX, but lately have been using Quaker State synthetic 5W30. (Will use the German Syntec once I find some.) The reason for choosing the Quaker State is that is is one of only 2 5W30 weights I could find in Canada that meet ACEA A3. The other being Petro Canada synthetic($10 a liter!) So even if it is a Group 3 synthetic, (some say it is a Group 4/5), it can't be all that bad, can it? I know that is a tough spec to meet for a 30 weight. Also, I agree that Audi is going to be in big trouble to recommend 15,000km service intervals, without specifying a synthetic oil! Dealers are charging extra for a synthetic, so obviously whatever they're using doesn't meet ACEA A3! Does someone smell an eventual lawsuit from poor unsuspecting owners with blown turbos!