I'm not sure what to ask for it, but it would probably do even better parted out. It cost the previous owner a decent amount of money to purchase and build this one. I do not believe it is 100% original, and has some upgraded parts. The condition of the frames paint may discourage some buyers from paying up for the other higher end parts.
If you check e-bay, the last set of spin rim brake wheels sold for $580.
https://www.ebay.com/itm/Rare-Vintage-SPIN-Tri-Spoke-Carbon-MTB-Mountain-Bike-Wheels-NICE-/173413398159?hash=item28603e768f:g:52AAAOSw~jJbS9r2&nma=true&si=NUqc0%2ByPTE1jGsjn9g6gxgj0w%2Bo%3D&orig_cvip=true&nordt=true&rt=nc&_trksid=p2047675.l2557
Note: A few of the other past sales for these wheels have been lower. so that sale may have just happened on a great day. I'm not sure of the model fork, but that Bomber fork might also be worth something semi-decent as well. Alot of there models were pretty expensive back in the day. (I once spent a ton of money on a top of the line Bomber Superfly model, and only got one season out of it). It was one of my worst investments on parts, as It was never designed for someone of my weight. I flew off a 4 foot drop into a dried up creek bed, and that was the end of that fork. I haven't purchased a new shock in a very long time (Were talking well over a decade), and I am not familiar with the current technologies available today, but my new at the time shock purchases after that experience have all been coils shocks and they still work well to this day.
I do not know what you payed for it, but I suspect you found yourself a nice buy and can make a good profit if you sell. If I found it at a decent price, I would have picked it up just for the wheels alone. I always wanted to try those out.
If it was mine, I would probably keep the wheels for myself, toss on some slicks, and use them to cruise around. And then see what I could get for the rest of the components and parts.
Here are some recent sales of complete bikes to give you a idea:
https://www.ebay.com/itm/Gary-Fisher-Joshua-F4-8-Speed-Mountain-Bike-USA-/263764439125?epid=1866006878&hash=item3d6995f055:g:a-gAAOSwkcFbJznm&nma=true&si=NUqc0%2ByPTE1jGsjn9g6gxgj0w%2Bo%3D&orig_cvip=true&nordt=true&rt=nc&_trksid=p2047675.l2557
https://www.ebay.com/itm/GARY-FISHER-JOSHUA-MOUNTAIN-BIKE-/332666777279?hash=item4d747c2ebf:g:SqEAAOSwuHFbDHba&nma=true&si=NUqc0%2ByPTE1jGsjn9g6gxgj0w%2Bo%3D&orig_cvip=true&nordt=true&rt=nc&_trksid=p2047675.l2557
https://www.ebay.com/itm/Gary-Fisher-Joshua-F4-Large-Frame-Full-Suspension-Mountain-Black-Bike-/112448944880?epid=1866006878&hash=item1a2e7abaf0:g:7gMAAOSwFqNZSDAh&nma=true&si=NUqc0%2ByPTE1jGsjn9g6gxgj0w%2Bo%3D&orig_cvip=true&nordt=true&rt=nc&_trksid=p2047675.l2557
https://www.ebay.com/itm/1996-Gary-Fisher-Joshua-X-Spin-Wheels-Fully-functional-bike-buy-and-ride-/142793919523?hash=item213f2e4c23:g:IcoAAOSwm-ZauBkZ&nma=true&si=NUqc0%2ByPTE1jGsjn9g6gxgj0w%2Bo%3D&orig_cvip=true&nordt=true&rt=nc&_trksid=p2047675.l2557
Look at the last listing posted in particular, this is why I would personally consider parting it out, or at least pull the wheels, and sell the rest of the bike with a substitute set.
It looks like you might have a LX or XT crank set, and I think maybe cheaper less expensive break levers and shifters. What are the derailleurs? If some of your components are xt or better, they can also get a decent return.
