I have no doubt that the car is fast. But dude, it has 306 000km on body and the car is almost 20 years old. No matter how fast it is, parts will break eventually (very soon). I'll pay 5k maximum, part out everything and sell for 800$.
He's just pissed he dumped so much money into an ugly, impractical piece of shit.
Bet you anything he got a girl pregnant.
6-8k depending on how badly you want it and how much he's willing to negotiate. DEFINITELY not 11k, the guy would be laughing his way to the bank.