c'mon guys, this is a gsxr, not a ninja. Kaw's have the absolute worst resale of any of the jap bikes. Suzukis tend to hold value pretty well. His price is not that far off. I'm guessing, like most, he priced it on the high side of average, leaving some negotiating room. If someone is selling this bike for $3 or $4k, he's wanting it gone bad. I'd pick it over a gen 1 or 2 anyday.
And i know he wants to sell it to get a 1000, but i guarantee it's not because he's reach the limits of what it's capable. Those are damn good track bikes.