Well, one of my changes with Amsoil 10W30 (a high 30W) with just over 5000 miles, the UOA was fine. Most people on the 3Si board seem to be running a 30W in lieu of a 40. Guess it may depend on driving style, quality of oil and climate. I don't have the valve tick that many of the owners complain of on the 3SI site.