Has anyone gone high miles on 0W20 or 5W20 oils? 300k miles or more? You hear about engines (older Lexus in my case, 328k) on 0W20 (Signature) and also 5W30 Amsoil (HDD and Signature). I always did oil analysis and the HDD actually did best. But to be fair, the 5W30 didn't get its 25k+ mile analysis, car was totaled and I didn't put the effort into analyzing it. I have a 08 GS450h now, will do first oil change at dealer on Wed.