Best car BMW makes in its current line up. Only major problems I see them comming in for are control moduels going bad, which are covered under warranty and a few recall problems which are easy fixes. Since the rims are 19 inch with low profile tires the rims do tend to get bent easly. Are you looking at the coupe or the vert? Auto or 6 speed? Eather way they both are great cars, but pricey.
The 08 have the updated exterior, front end, rocker pannels, trunk lid. Also the interior is changed around a bit. The 6 series are personaly my favorite car BMW makes, a coupe with a beefy v8 makes me drool.