2.0 GTVs aren't thin on the ground, so you'd be wise to wait for one that has been looked after, I reckon. Hopefully that way you'll get one that's had some of the big jobs done on it, rather than one that's about to need them all doing. If the owner has been doing the bare minimum to get it through the MOT each year, you could end up spending a lot to get it into decent shape.
Apart from the cambelt, at that mileage the suspension bushings may be starting to go, the standard copper radiators start to corrode and fall apart, and then you have things like brake discs and pads, and air-con, which are more likely to be in good nick if the car has been looked after. It'll save you money long term if you get one that's had some of that work done, and has the receipts to show for it.
Specific to the twinspark, those engines tend get through oil, which is fine if the owner regularly checks it and tops up, but if it's allowed to get low it can lead to bottom end failures:
(Usual advice is check the dipstick and walk away if the level is below the min).
There are plenty of good ones out there, though - as you say, worth spending a bit more on.