Between those two choices, I say go with the M3. If you want to spend a little more, but have something that could take you farther in the long run, find a early to mid 90's porsche 911. You would probably end up spending a lot extra on either of your two choices just to make it as capible as a 993 Non turbo. You can find them on ebay selling in the low to mid $20k's

like this

http://cgi.ebay.com/ebaymotors/Cars-...m130229664800&






just my $.02