I have a 330Ci with just over 1200 miles (sport package and stock wheels and tires, Continentals)and on a trip this morning I started to experience an intermittent vibration (like running over rumble strips but not quite that severe, but VERY noticable). I stopped to investigate and couldn't find anything wrong (ie: no wheel weights missing and no flat tire). When I started up again the vibration was gone but then came back a few miles down the road. I stopped and started several times and sometimes the vibration would immediately come back and other times it would be smooth until I slowed down and stopped and then started again. On the highway it seemed worse at 55-65 mph and smoothed out around 70mph. I've also felt it when traveling slowly up through the gears but at other times from a stop it was smooth. I know it wasn't the road surface since I traveled 150 miles this moring over different roads. Obviously I'm going to the dealer tommorrow but if anyone has any ideas I'd love to hear them. Thanks for your help.