I have an HPAR which I just love. Custom Wenig Stocks, Case colored side plates (Doug Turnbull), two trigger groups, one pull and the other release. Unmolested. This gun will NEVER be for sale by me. There are many 90T HPAR owners who have the same feeling I suspect.
Be aware that to have a 90T updated by Doug Breaker (forearm lock mechanism, locking block work, new spring kit and recoating of receiver, trigger group and barrel), well that is over a $600 investment and a layup of about 8 weeks or so.
Most HPARs I have seen are well used, and rightly so as these are good shooting guns. Unless the HPAR was recently worked on by Doug or Kolar, then the "tune up" fee needs to be included in the overall cost. That said, a tuned up HPAR is easily a $3,000+ gun.... less if someone has mucked the barrel up with choke tubes (my opinion).
The low rib 90T, which is way more common, (I have one of these also, and it is at Breaker's right now), is perhaps a $1,700-$2,000 gun if right. Mine is having the complete upgrade, recoating, spring kit, locking block and forearm work done. This is also a fine, fine shooting gun. The long tight full choke barrel is really deadly if you are "on".... not so forgiving if you are "off". I am sure most experienced 90T owners would agree on that aspect of the gun.
The 90T with the full choke and 34" barrel (I have not seen a 32" barrel on one), is a great back line game gun for Wipe Your Eye, Annie Oakley and Doc Adams....
Art