GTV lasts pretty well. The engine is quite reliable if you look after it. That means keeping to the service intervals (12,000 miles officially, 6,000-10,000 is better) and religiously changing the cam-belt and tensioner at 36,000 miles. Use the best oil you can afford and don't buy crappola parts from eBay.. just proper brands that you've actually heard of.
The rest of the car will peter out around 180 ~ 200,000 miles but I dunno why you wrote it "only" lasts that long.. that's 20 years to most people, so you'd get your money's worth.
Everything will wear out between 150,000 and 200,000.. suspension arms and bushes will go first.. and you will eventually need new bearings and dampers at around the same time... so you'll become friends with your suspension provider..
If you ignore suspension problems, get friendly with someone who can weld aluminium because you'll wreck your subframe... You can buy Cyprus cheaper than a new frame...
Radiator will be knacked and the water pump could be due a change by now, if you aren't changing it every second or third cam-belt (108,000 miles should be okay for a pump but 144,000 is taking it to the outer limits).
Fuel pipes and lines might be perished and your brake pipes will need attention (both the metal and the rubber ones).
Everything else in the engine bay is not bad - alternators, steering and starters, braking system etc. seem to be fairly robust and not your biggest problem.
A lot of stuff will also be Killed in Action, rather than worn out.. years of battering might eventually get the better of your fog-lamps, indicators and light lenses... and various bits of trim will fall off, become brittle or crack and split... but there's still a few cars around to find spares. Buy new stuff, rather than second-hand, if you can find new stuff. They're not making any more of it, sadly...