what Simon said.
S2 and S3 are pretty much the same car underneath, so it's really the cosmetics and condition that matter here.
Aomw things I'd be checking on both prior to buying - not that these are showstoppers, just things to get fixed if required.
steering rack (is it heavy at start up? Means it's on the way out.
Fuses,
Screenwash tubes (leaks cause electrical gremlins),
door seals
roof alignment
Door alignment (are they drooping or do they close smoothly
Good luck with your purchase!
