I base the 8K number on the stated condition (very good), and extra dies and tooling to go with it.
Some recent sales on fleabay for mechanical hammers : Rebuilt Little Giant 50 lb@ $5000, rebuilt 25lb LG @ $4306, Kerihard 30 lb @ $3250 2 more LG @ 2800 ea, 1 25lb , 1 50lb, and no longer listed the anyang/striker 165 that sold for aprox $7800, about 1/2 of new value.
Also a big blu 155 on there with a buy it now of $5900.
Kuhn is a way better hammer than any mentioned above in my limited opinion. Is 40% off of new a fair price if in new condition?