They have weak points for rust; rear arches, boot lid around the lock and a few other places.

Vapour seals is another slightly weak point - they prevent water getting into the car....so check the carpets in all the foot wells, if they are wet, the door card has to come off and the plastic seal, needs to be re-fixed; DIY job with Tech7 or similar.

Suspension will be well on at this stage too.

If possible, try buy off an enthusiast; these cars are at the age and price that they've passed through a fair few hands, or the wrong hands, so its best to buy one with a service history / known to be well looked after.