For me it would be the Lotus Exige S1... possibly save a bit more for one with a decent power engine in it.
Ahh lotus. 20k would get me in a decent V8 Esprit. Always wanted one.. Found I was just too big for it really, at least to fit in it with a helmet so it could get used on track.
Always wanted a ferrari dino GT4 / mondial T coupe. Not sure why as neither particularly the most loved of dancing donkey line, but a certain 80's greatness about them I think. When I ahve a big enough barn I'm sure a GT4 will be found. Can see it as a top fun everyday summer fun car for nipping down the shops.
And an Alvis TD / TE 21 coupe too - lovely looking things, for me has the presence of an aston, at sensible money
