Agree w @Ohmess - swapping in a full interior from another wrecked/rusted coupe would probably be the easiest, most direct and potentially more affordable approach. A good portion of E9s need their chassis restored so the same holds true here. I believe Spain has a much lower hourly rate for knowledgeable body shops and Portugal is next door so it comes down to how badly you want to do it. Do you LOVE the car? Have you undertaken a project like this before? Personally, I think it's quite unique but I'm from Miami and I love verts. It's a decision you'll likely make with your heart and not your head. It'll be a hellava costly, frustrating adventure but you may, just may be glad you did it!