I recently purchased an '06 650i coupe (black on black) and love it. The car is very clean and runs like a dream.

However, I took it in for a service and to have the tires checked etc. It seems that I have front 18 inch ellipsoid sport wheels in the back as well as the front and not the 19 inch wheels that I should have. The dealer said that I cannot drive it hard and to be careful cornering etc etc. "This is not what BMW specified etc."

Is his concern well founded and do I need to go out and buy new rear wheels and the $500 a piece run flat tires? I bought the car as is (it has a clean car fax etc.) so have no redress with the seller.

Thoughts would be appreciated.