The biggest issue is previous owners, shoddy maintenance and shoddy tuning work. So once you can rule out any issues there.....you've a good starting point lol.

External bodywork can get shabby around arches etc. Up inside the rear strut turrets can rust....almost always rust. So that will be an MOT issue if they havent been sorted

It 140k I'd be surprised if it hasnt needed an engine yet given how poorly most are maintained.
So it would be worth checking engine number. A Replacement might be a good thing, or another huge variable.
Always nicer to know it was rebuilt by a competent person, than some cheap POS thrown in as a replacement

But then that comes back to my original point about knowing it's history.

5speed boxes arent strong, but a good one works fine. Clutches can be an issue as with most 4wd cars...again, when they go some people throw in cheap crap, others replace properly

But it's an oldish car now, it's hardly an expensive car, so you'll hardly expect it to be a pristine well maintained example.

Head gaskets are rarely an issue though ( unless blown through dodgy tuning or from overheating due to other causes )