Don't know if you are talking about my 1680 i have for-sale on Sioux City craigslist (located in Omaha NE) , but i have 3600hrs, chopper, field tracker, long cleaning system, long auger, crossflow fax, but no rock trap for $25,000 (obo). I would not put $40,000 into it - you might as well get a 2388 for that price.
I have close to that in my other '90 1680 set up the same way just with a new motor, new rotor, and all the other work i have done to it (3200hr). I would be lucky to get $35 out of it.
If you have that kind of money sitting around i would be thinking of a newer machine.