At that price I would be concerned about a number of things:
- engine - Early models - engine liners (they were changed after a certain engine number - info easily available). All models - have tensioners been replaced (can be subject to catastrophic failures of old "plastic tensioners", also check for guide wear and early type water pumps - loss of coolant must be investigated
- rust - there would be the obvious but particularly in front sub frame rear mounting points and rear suspension mountings - also check the rear of the inside of rear wings - check in boot on inside corners - also around floor pan
- worn suspension - everything - they are heavy cars - but particularly shock bushes - rear shocks themselves - check for "skipping" when hitting bumps or cornering
- steering rack - check for wayward feeling
- gearboxes which were supposed to have been filled for life often start to develop issues when they hit 80k and over - this can often be solved by getting a specialist to power flush and replace filter - check codes etc - e.g. Dartford Transmissions
- be particularly wary of an EML which is anything to do with Network CAN controller or similar - this can be a particularly difficult fix (symptoms are loss of gauges, gearbox locked)
- a bit like 350Z they don't like anything but a perfect battery. A less than perfect one can throw up all sorts of "phantom" issues which, upon replacement, can just go away
There are some good buyers guides (books) and loads of information on the XKEC forum.