Well today I changed from M1 back to Castrol. I put Castrol Syntec Blend 10w/30 and a K&N filter. Went back to 10w as the temps are starting to break. My 2.7L Tacoma sounds quieter than with either the M1 5w/30 or 10w/30. I'm gonna run it for 3000 miles even. If I got $20 laying around then I'm gonna run a UOA. Judging from the latest Syntec Blend UOAs I should do just fine with this particular oil.