If you can swing it, keep it. And buy a 3rd Gen as a DD AND leave it stock. 3rd Gens are awesome, they do everything well. But, 1st Gens make great toys. (hence my WTT for a 1st Gen thread). I'm only looking for one because I'll still have my 3rd Gen DD. And your toy is already well built so you're further ahead of the game then I would be.
Why lose $5K selling yours just to spend another $5K building a 3rd? Keep your trail toy and take that $5K you would spend on a build to buy a nice 3rd Gen to DD.
My $.02