You won't find M1 10W40...if that's the weight you like and you want a syn, I recommend Redline 10W40 for your engine, although if it were me, I'd go with their 10W30 if the engine is healthy and not using much oil. What weight does your owner's manual recommend?
i think he wants to go synthetic.
he drives pretty normally, but I would say alot of stop and go and up and downhills if that makes a difference.
stalls on occaision since he just started stick so might need some extra lubrication for those times? (does that make a difference?)