No bias here, but it's the pick of your shortlist by a country mile [

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Search on things like buying advice (or just have a look through - there aren't that many posts on here yet).
The big Achilles heel of the S2 is the cam chain. It's a simplex which wasn't exactly over-engineeried in itself and it uses a nylon slipper as a tensioner, and as if that isn't bad enough it wasn't checked as part of the main dealer maintenance schedule[

] These days everybody who you would want to trust to look after an S2 knows all about it but in some cases the chain has worn excessively and has damaged the sprockets. They are integral to the cams so it's not a small piece of work to correct. Also I know personally of several cases where the case-hardening on the sprockets is failing which ultimately results in broken teeth. Many S2's you see advertised have had a recent chain and tensioner, but just like you don't replace a motorbike chain without renewing the sprockets at the same time I personally think that's a worthless thing to do if there was any wear at all apparent in the chain - and I'm guessing a lot of chains don't get replaced if they don't look worn.
Don't be put off though - I bought my S2 cab at Easter last year despite having had missing teeth on the cams of my previous S2 coupe. Because it's impossible to trust the condition without someone experienced actually looking (mileage doesn't help much) I bought it at a price that I felt took into account the cost of replacing the cams if they needed to be (and guess what? They were replaced within a fortnight).
Other problems are the usual stuff for any car: accident damage, water in the oil, clunky suspension etc. but nothing you wouldn't expect to look out for on a car that is now at least 12 years old (and you shouldn't see any of them, of course).
Clutches you mention and they can be a problem as the centre is a rubber bush rather than springs and it can break up before the friction material is worn (been there, done that in my coupe too [8|])
On the bright side I have 162,000 miles on my cab (and 153,000 on my Turbo) and it still feels like it always did (I guess - 60k is about the least used I've driven). Trim wears well, it's galvanised so there should be no rust (although where the bottom of the wheelarches gets blasted with stones can go a little, especially with wider rims than standard) and if they are well maintained they are very reliable.
If you're seriously considering a Fiat or a Lotus then you can't be scared of the spanners!
I'd pay £5-£6k for a nice one and be prepared to spend another £1,500 sorting out cams.
Oh, you asked about figures. I think the S2 was 6.1 to 60 and 149 flat out. 30-70 I could only guess at, but in the right gear fairly quick.