Just caught up with the thread and couldn't head off to bed without posting.
Firstly, I am an absurd S2k fanboy. I absolutely adored my car, and in the end it went due to financial reasons, ultimately I could only have kept it by cutting corners and I couldn't bring myself to do that. With that in mind, take my opinion with a pinch of salt.
I think the first thing I should say about this thread, is your comparing a golf in a fat frock with the car Honda built to celebrate its birthday. Its an incredible machine when you consider everything, even if the early ones didn't have a clock !
You desperately need to drive both, but get a decent drive of the s2k, and drive a good one. If you drive one with the geometry out you won't enjoy it anywhere near as much and it will feel like a deathtrap.
The s2000 is a balls out, high reving rwd roadster that on the right sweeping A road at night with the roof down, airbox lid off and the heaters on full will make you wet yourself every time you nail the throttle. Nearly everyone I took out in the car laughed with joy when I floored it and hit the magical 6250 rpm.
Please. Please. Please do not buy a car for 4k. or even 5k, or probably, even 6k. You desperately need one that someone paid 10-12-14-16k+ for, and has treated it with loads of respect. These cars get very expensive when things go wrong.
The biggest thing with S2000's is suspension. EVERYTHING is about the handling. You can spend cash on engine mods (see further below) but handling is where its at. I spent thousands on mine sorting the suspension out (Seized adjustors, getting new springs, uprated anti roll bars, brace bars, poly bushes etc) and it was absolutely incredible after.However, it was so hard core it became tiresome on the roads, and the track was the only place it made any sense. Doing it again I'd have considered different options.
Power wise... you can get decent improvements with an AEM EMS 1042U (I think?) with a map from Mase in the USA. He comes over regularly and you can get 20 or so BHP in the midrange where the car can feel weak. Intake mods are expensive but solve heatsoak issues, and exhaust mods make the car sound like a race car. Your looking (for new parts) at probably close to 4 THOUSAND POUNDS to get a decent Intake (J's Racing/Mugen), decent Manifold (J's Racing/Mugen/Amuse/Hytech) and then a decent exhaust (again, J's/Mugen/Amuse/Hytech/Greddy Spectrum Elite etc) along with that ECU correctly mapped.... You might get 30-40 bhp peak extra on the top end of an early car (pre 2002 which run very rich) but you will definately get a race car sound track and incredible pickup.
Similar money gets you a supercharger or a turbo. Phils2K in the UK shipped his car to the USA to get turbo'd and acheived over 600 bhp on the stock engine block. However, turbo/superchargers aren't reliable on track and the car just overheats.
I could go on and on, but I'll just show myself as a stupid fanboy. Ultimately get in the car and see if you like it. It can be great fun, but equally it can be a money pit and totally not what you are after. See what you think.... but please, spend the money and get a decent one.
As fox says with E39's and E46's they are starting to become cars that you need to be an enthusiast or spend 'more money than its worth to get one' .... Don't let this put you off getting one, but just go into it with your eyes open.
If you were asking me now what I'd get, I'd get a long term enthusiast owned facelift non GT (just means no hard top) 04 car without VSA and using the cable throttle (DBW as of 06)
I'd then get the geometry done at Wheels In Motion for £100 quid, ensuring it had the right tyres on it (Bridgestone RE050A's, the car feels weird without them and it ruins the handling) fit a baffled sump, oil catch tank and oil cooler for track days, as well as buying some extra wheels with R888's fitted and track the absolute hell out of it.