I am thinking about buying a set of 18"BBS forged RC wheels for my '98 1.9 Z3. They are either 8's or 8.5's and the owner of the wheels is not sure which they are. Are 8.5's too wide or will they fit? Also, am I out of my mind putting 18's on my little car? The wheels came off of a 325is. Any help would be greatly appreciated.