Hi,
I've had two S2000's and an Edition 30 GTi .... I don't have either any more but love both the S2000 and regret selling my edition 30.
With a remap the Edition 30 is quite a bit quicker than the S2000 but they are totally different cars! FWD v RWD convertible.
You wouldn't regret getting a GTi after an S2000 so long as you realised one is more of an all rounder whereas the other is a RWD top down screamer :)
The standard GTi when remapped would seriously surprise an S2000 but the S2000 experience isn't all about speed and I always used to get out of mine with a smile on my face.
I found the bigger turbo of the Edition 30 pulls seriously hard at higher revs when remapped and this gave me a bit of the 'feeling' I enjoyed so much with the S2000.
Handling wise I have found both are great but again, it is all down to the FWD or RWD feeling and what you like. The Golf certainly won't disappoint with it's handling but the S2000 feels likes it's going quicker when in reality the Golf is probably the easier to drive.
I can't slag off either .... they are both great. Go and try - but if you can stretch to an Edition 30 I think you would prefer it .... but I am biased