I dont think OP is in for an E46 M3. Think he has the v8 bug. In which case E9X M£'s are dropping into the 17s now, given they are high mileage but you can negotiate a lower mileage one down quite a treat. It is a buyers market after all.
I asked your budget because I think there are some lovely cars out there sub 20.
such as the E60 M5 ballistic. Some very nice porkers. also some decent older AMG's for an unbeatable v8 soundtrack. All of which are more refined than the vxr8. No i havent driven one. SO yea my view is somewhat flawed but to be fair Clarkson is a fanny.
Still though either way. Interesting... very interesting.