What's a fair price for an Audio Research Reference 75?

I have recently heard from a couple guys that had bought new ARC REF160s and just couldn’t part with their REF 75’s. Once owned a lot people really just can’t part with them. 

Looks like around $5K.

The HIFiShark site has sales records of more than 20 REF 75s on US Audio Mart. Click on the "Sold/Expired" tab at near the top of the page, then click on the "Site" column heading to group the sales by where they were sold.
https://www.hifishark.com/search?q=Audio+Research+Reference+75

$5,000-5,500 in excellent condition