my MINI Cooper had a 15k oil life on Castrol synthetic, neeless to say I still changed it at 7500 on my S and 10k on my Cooper. My Ford E-150 cargo van that I used for work, I put 130k on it using synthetic changed every 10k

I switched the HHR to Mobil 1 the day I got it and the oil life indicator seems to just about where I would change with synthetic. Not that being said, I can't even imagine running conventional oil for 10-15k.

I use the 0-30 syn with no problems. actually reccomended for winter operation---Budro