Hi Rich -
Having bought and sold a TON of cars in my years (including an 04 G Coupe), my stock answer is this:
It's worth exactly what someone pays you for it. I realize that's not terribly helpful, but here's some additional pointers:
The aftermarket parts add zero value - some may be excited to see them, some may see them as a detriment. Also, it's not up to you who buys it - G Coupe lover or not, whoever get it, gets it (odds are, if they're not a fan, they won't buy it). Lastly, the backstory, while useful if you were keeping it, won't help (or hurt) its value.
With that said, I'd look at similar-condition cars on AutoTrader, Cars.com, and Facebook marketplace, and also price it out (private party value) on KBB. Then I'd take good photos, price it $1k over the average of those numbers, list it, and let the market do the rest.
Good luck, and keep us posted!
p.s. You'll want to mention if it's a manual or automatic as well.