For me being a coupe would be a hinderance, I'd love to find a Subaru of that vintage with a 5 speed manual. I had the 1.8L in a 1985 GL wagon. That particular car ended up having a situation with I believe frequent low oil pressure, I believe it had an oil gauge, like my 20 year old truck.
I wonder if the 1.8L engine has the same good reputation overall as the 2.2L? If I was in the market I'd buy the car for what it is - a coupe wouldn't be a show stopper because it's such a rarity with the 5 speed manual, and IMO a good looking era. I wouldn't modify it in any way, except for the radio. But I've never been mainstream, and probably around the same age as the interested buyer's parents.