I used the recommended castrol TWS for a while in my M3 (s65 engine) and recently switched to M1 0w40 a few oil changes ago. UOAs have been good with the M1 but I have been thinking about a different combination... What do you guys think of running a 50/50 mix of castrol TWS and castrol 0w40? Any reason it would be a bad idea to mix these two? I'm wondering if it could be the goldilocks "perfect" mix of cold start and operating temp protection. Thanks for any input!