No more than $4500 with those wheels and the bumper like that... sorry but those 'mods' devalue the car from stock... I'd pay $5k with some decent Pony or 4 lug Cobra wheels, a new GT bumper and the proper GT tails... with an underhood detail and a Cobra bumper to properly match those tailpipes the car might fetch $5500. But you're gonna need to put some money into it right away to fix the cosmetic issues and do all the back maintenance...
Don't forget that any car that sits for several years = lots of maintenance to do... expect to need all new fluids... there's probably lots of shot rubber parts on the car i.e. all your hoses,
suspension bushings, quite possibly the tires too... that's at minimum