I'm looking at doing excatly that. Not an M3 though - over here an S2 cost a little less than a mid 90s M3 and has the benefit of classic insurance, whereas the BMW doesn't so I couldn't afford to insure one at 23.
The cars that are tempting me at the moment are TVR S3's and 350i's - 2 seat open sportscars with a nice compact V8 in the front
