A good friend of mine is considering a '99 A6 quattro...any tips/pointers on specific things to look for with this year vehicle? It's got just under 50K miles on it... Didthe V6 engine change from 12 to 30 valves at some point? Would a '99 have the later engine? TIA, Lee '95.5 S6 avant '96 A6 quattro avant