Hi, I'm looking at a 2006 A4 1.8T 163BHP Quattro with 26K miles. It was first registered in September 2006. It has the following Audi service history - 15th Oct 2008 @ 11,750 miles - 06th Jan 2010 @ 20,500 miles The dealer who is selling will service again before the sale. I've read much about the problems these engines have with sludge. Is this service history a cause for concern? Thanks, Mr.