Surely people collect these bikes/frames who might want it?
Not Kleins of that age I’m afraid, its well past the Trek buyout, where the proper Klein sobs will tell you it’s no longer a proper Klein, and also right at the end of the cross-over point where they were the old Klein designs being made by trek (still has the Klein dropouts facing backwards by the look of it and internal cable routing), it’s almost into the ‘Trek with Klein-stickers’ era.
It is however still a very well built, nicely lightweight, racey hardtail frame with good XC geometry, and you should think of it as such, just don’t go expecting the Klein name to add much value on a frame of this era.
If you were selling frame only you’d probably get £80 – £150 (maybe a smidge more if you were really lucky!) for it I think, as a full bike it’s gonna be awkward to shift due to mis-matched bits, you’ll get more for it by splitting it up.