I bought my 88 from a guy in Lake Havasu City for $400, trailer included. Ya, it needed some work but just minor stuff. I've noticed that in this area, the older 2 stroke stuff is getting more affordable with the growing popularity of the newer 4 stroke bikes.
MHR & Iceracer are two very good builders. FTZ has been advertising their work on the Quadracer for a few years now also. Hopefully as soon as I can get my finances back on track, I will be helping HPR with his continued 250 development as well.
I don't want to leave anybody out so if there are other good quadracer engine builders out there, please let us know.