Usual coupe spots for rust (where mine has it....
)
Lift boot carpet right up and look in the seam of the boot to the wing
Bubbling around rear arch or pinafarina badges - moisture gets inside the rear 1/4 unfortunately and rots from inside out
Under bonnet look at uprights on around where the horn is (Left hand side as you look at it)
Unfortunately rust is the biggest thing, remember - these cars are over 25 year old in some cases now. I've been around classic cars alot growing up so it makes me smile when people say about a coupes rust and not going near etc.... - When you've looked at a 70's stag (or any car tbf!) thats been sat in a barn for 18 years then pulled out, now thats rust. And people then dont say "Dont go near it as the holes in the floor are over 3 ft" - They get restored. And look at any mk1 golf, mgb restoration etc.
The coupes just in a weird phase of its life now where they're being tipped as future classics (and indeed good ones are now north of 10k!) but people with them still see them as a cheap fun car and not worthy of restoration. Tides turning and i'd guess that the specialists are seeing more restorations that servicing these days and i'd also expect that to ramp up as time goes on and numbers dwindle further
Lee