That's the older, second-generation (partial monocoque) Enduros. Still fine machines but not nearly as heady of worth any more. Thousand-ish might still be reasonable if it's super-sano and if it's to the '04 side. They hung a lot of good parts on them.
A Bikepedia check may help narrow down the year some:
http://www.bikepedia.com/QuickBike/B...&Model=S-Works Enduro&Type=bike
http://www.bikepedia.com/QuickBike/B...&Model=S-Works Enduro&Type=bike