...the price is too high considering you have an overhaul coming up. If it was a 1000-1200 hour engine, I would think that to be a pretty good deal.
If this plane is expensive at 2000 hours at $20K...but a good deal if it had 1000 hours -- then half an engine job is worth $5K??
I would think that there should be a linear relationship between hours and dollars -- given a fresh engine is $15K.