My STTNG in all it's glory can be found here: https://pinside.com/pinball/market/classifieds/ad/46445
BTW, I think I may be a touch over priced given that the last STTNG that sold around here was in Santa Clara for about $4500.
The NGG I am being offered is a straight across trade. It appears to be very clean, with little to no slam ramp wear, and the insides are so clean I don't think it was routed. The exterior is in pretty good shape with only some small scratches on the head.
My initial reaction is that my machine may be worth a bit more, but not much. I am trying to work out a fair trade here... What should the values of the machines be in this trade?