Should be completely based on the MU of angel male, plus upgrade costs. A quick wiki looked to be 700-1k per part depending on if the MU's have gone crazy- or are impossible to find. I've seen some people upgrade lately so the components must be available.
Angel male is what, 13-14k on a good day for the seller? So if you somehow expected to re-coup all upgrade costs/MU, 20-21k. I'd consider those prices the best case scenario for a seller. The above mentioned 18-19k range would be much more likely.