Well, the CSI is the most rare of all. They most have 6 speed manuals and the rest have 4 speed autos. I have a 91 850i and they are very reliable cars to own. The aftermarket for this is a pretty much custom deal, so this is where the $$ is needed. If not, the parts are not more expensive than the other BMW models.
Karrbass...$24K for a 100K mile car is a bit too much, what year is it? 95 maybe?
MikeyZ325...I went to the 8-Fest and there were 57 8's and 61 owners present. It was so much fun. Look at the links below for some info...click on the "Daily Recaps" close to the middle of the light blue "8".
http://www.8-fest.com/events/recap.cfm?EventID=6