Seriously, with this engine and oci's required for warranty, I see no real advantage to the 10w30. It isn't a turbo and I don't think it's that tough on oil. I can't believe the sludge monster rumors. I doubt it. I would prefer the 5w30 at least in Winter. I wasn't that impressed with the real world cold crank of M1 10w30 around 0°F. I have had the same battery, too. M1 10w30 is like a rock, but unless you have certain turbos or consumption issues, I see no advantage.