Freestyle, nox reloaded, custom anno/milling/grips done by acidrain, HE bolt, proto barrel
I would think you might get $150 - $175 shipped. FS8's with reg ups are selling for $200-$250 right now. I bought my Gen 2 with HE and barrel, both regs, grips, feedneck, and trigger upped for $100 shipped to Canada. Yours looks way nicer.
^^^ You've got pretty much every worthwile upgrade you can get for the Promaster, but that doesn't mean people will spend any more to pick up that marker. Stock Promaster resale is around 60-80 bucks these days, so don't expect anything over 200 for it.
Priced at 175-200 it will probably sit on the market for a while, but eventually move.