I built up my own S-works equivalent Enduro in 2014, on an Expert frame which is FACT 11M, I may be wrong here but as far as I could tell when doing my checks the Enduro Expert frame was the same as the Enduro S-Works frame (both FACT 11M) but with a different paint job. I bought the frame and fork secondhand and all the rest, except the wheels, brand new online from Germany (cheaper back then). The whole build cost me £4k A new S-works at the time was around £7K+ !
My spec:
Enduro Expert frame (L) FACT 11M
Rockshox Pike RCT3 Fork 160mm
Shock: Fox X (kashima)
Wheels/Hubs: Roval Carbon Control SL (hubs roval dt swiss)
SRAM XX1 complete drive train
Renthal Carbon FAT LITE bars
Renthal Stem 50mm
Brakes: XTR 203/180
BB: Chris King PP30
Command Post IR
Pedals: DMR Vaults Mag Superlight
So yes the S-works are definitely overpriced!!