I just purchased an '06 DB9, 6 speed, coupe, 20K miles - wonderful car, well maintained. Everything is good but local AM service noted, as I did, a bit of a tappet noise. Any others experience this problem, comments? Consensus was to ignore unless it gets worse. AM specifies Mobil 1 0W30 or 0W40, but I've been thinking about trying 5W40 synthetic (Redline) unless AM gets cranky about warranty.