it all depends on if you want a left hooker or not. golfs, as tom says, are alot cheaper on panels and the rest of the parts but engines are the same. corrado's weigh alot more than golfs and i've never been impressed with any of the g60 corrado's i've driven, tuned or standard.
i'm with gibby, if it was my money i'd be after a vr6 corrado then spend another £2k putting a charger on that!