Whoa there matey! Quite a find....and a major undertaking at it. No doubt, when done, the car will be highly regarded. But it depends on where you draw the line between junking the body or salvaging it. Judging from the pictures, I would lean towards saving the body, but certainly plan on investing $10-15k alone on metalwork and rustproofing alone to get the body the way you want it.
The 26" radiator that is still in there commands big bucks today. I'd offer $3-5k cash provided the car has a clean title (CLEAN title, no liens, no photocopies, the real McCoy). Look under the carpets, rear seat, and under the package shelf and see if you can locate a broadcast sheet. I'm assuming the fender code tag plate is missing, since you did not take pictures of it?
B5 blue or FC7 plum crazy, that is one find! 440+6 with rally dash and column shifter!? Gorgeous!