OK, not only did I change to M1 yesterday (10k miles) but I also took the leap of faith to go with the now recommended 5w20. That part was hard. I stood in Pep Boys for 20 minutes looking at the bottles before grabbing the 20. I'm so old-skool that anything less than 10w40 was hard for me to use, let alone 20! Anyway, my 2006 Scion tC seems happy so far. No noise, and it's very smooth. Time will tell I guess, and this is likely the batch I will run a UOA on.