One of Every M3 Generation for Only 75k!?

spent some time on Craigslist today and bookmarked a few interesting (read: suspiciously cheap) FS ads. I then noticed I had bookmarked 4 M3s - one of each generation. Just for fun, I totalled them all up and what do you know? 75k.
That's a lot of enthusiast auto for 75k. Imagine having spent that entire sum on a base trim SLK55AMG? Sure the E92 doesn't have a title, the E46 has high mileage, the E36 is probably wasted, and the E30 is in need of a massive overhaul... but hey, 75k. From youngest to oldest:
I'd be interesting to figure out which would be the most rewarding buy. I'm talking financially and over a 2-3 year time horizon. Craiglist posts don't exactly tell the entire picture, but one would need to take in to account the basic work that needs/may need to be done on each car listed above. 
And if anyone was wondering, YES I have already contacted the E30 owner and sent him a long list of questions. Methinks it would be a wise investment. ;)