I was going to say shoot for a replacement car, but I think you're loving the fact the car was built on the 50th anniversary. That is kinda cool. If you go for replacement car, skip the undercoat and paint treatments. Summer-only cars won't benefit, and you'll be waxing this thing enough to protect the paint.
In my view, go for door replacement next. The paint is highly likely to match. You'll have no-damage metal, and factory, baked-on paint. If it doesn't match well enough (and, I'd actually wait a bit to see if the paint ages to match), then get it painted/blended to match yourself, using a good body shop of your choosing. Angie's List is a good source there. You'll still have the undamaged metal beneath it. Many posters have been rightfully pleased with their repaint results. We've had some major work done on 2 cars - the blend was perfect, and the paint has lasted many years of daily, winter, salt exposure driving.
The fact that you had to find the damage without the dealer first owning up to it is horrible. Get this resolved and stay away.
This thread isn't about the definition of "investment," but you are right - know one knows. To me, if you can have a blast with a depreciating asset like a car, but have it depreciate dramatically less than say a Taurus, you've done well. Everyone laughed at my dad in the 70's for keeping his 65 coupe. "They're a dime a dozen." "It will never be worth anything." Could he have done better in the market with his 2,500 in 1965 dollars? Yes. Is his car worth more than the average 1965 specimen? Yes.
Down the road, I think your car will be worth more with undamaged metal, and hopefully all factory paint.
2012 Boss Yellow Blaze, Recaros/Torsen, Cover/Mats
2012 MCA PP Sterling/Lava