If you are going to take a "normal" Coupè you shouldn't have big problems. Not more than a "standard" car.
Just spare parts would be a bit difficult to find.
If you are planning to take a supercharged version keep in mind this: supercharged cars are bought to be "strongly" used due to high power engines, so you should carefully check engine status.
16 valve engine is a bit "stronger" than 20v engine and 16 valve is suitable for hard tuning (high hp increasing).
If you don't want to tune the engine (or just make a soft tuning), 4 or 5 cylinder engine are equivalent (20v turbo reaches about 250 hp of soft tuning).
20v turbo has got a linear engine progression (it seems like an aspirated), the 16v turbo seems like..... "a kick in the bottom" when turbine works.
Then, if you drive carefully (this means wait the oil reaches the good working temperature, wait the turbine stops without switch off engine suddenly), the engine will lasts long time.
Keep in mind you have FIRST to change distribution belts (it's very important: don't trust who says "it's just changed!", you could destroy engine), and maybe change the turbine (if it smokes at minimum or "eat" a lot of oil).