It runs fine.
It is high - yes (all these places like this are) but without digging trough the pictures in detail it looks like the underbody is solid and it is pretty complete. For someone that had time to fiddle with it and make it better by fixing small things , touching up and tuning it could make a nice driver without a high investment after purchase. I would not buy it if i was looking to fully restore unless there simply isn't another choice that isn't a rust bucket.
I haven't kept up with the firebird market, but typically camaros, firebirds and mustangs flip flop around on what brings the best money and Firebirds are rarer, I can see being one over a Camaro as a draw for some.
Also not every one wants a showroom car or has the stomach for a full on restoration. Id be surprised if you could buy a showroom condition one for twice asking on this one.
Yes 27 large a lot of money (would he throw you off the lot with 22500 or 25?) but it is not really out of reach like 75000 + car you are afraid to drive..... and go to some of the other collector car sites, you can pick apart even the higher dollar ones.