Good luck with the sale, sorry to hear about it though.
I'm thinking it'll be rough to sell that one for what it's worth. Sedans are unfortunately not worth as much as coupes. I paid $800 for mine in decent shape two years ago, though I got a little lucky. I'd not that good on guessing car values, but I'd say $2000 is pretty easy to get at if the car is in good running shape. Your upgrades should add more to the price.
Personally, I'd find a scrap sedan & grab some parts to make yours more complete...lights, trim & trunk lining will definitely help sell the car.