92 GQ TD42??? What to do

Okay so as the title says, I am currently looking at a supercharged TD42 with 380,000km manual. ST i think from memory, and the kilometers have been racked up in the country. So, given the Ks is this thing worth the 6500? The supercharger is a Sprintex and has been attached for 160,000kms, so I would say that it is a safe bet to say that the crank pulley is not going to snap off. It is running 9.5psi. Serviced religiously at 5000km. Just wondering if I am paying over the odds here. The body is in good nick and no rust, and from what I have been told, this is the most important thing when looking for a GQ. Any help would be great