Aftermarket mods will get you the most money when sold seperatley. If the car is "junk" as you say thats all people will see. If you want to get the most money out of the car I suggest parting it out.
I have done this before with a car that got t-boned. I bought the wreck because it was the only one in Canada that matched the color of mine and needed a few things. The rest I have been selling. It can be a long and slow process, but the net profit will be more then just selling the car as is now. Stuff like OBC, steering wheel, guage clusters, climate control modules and various interior trim pieces are all in demand.