I think it is a good idea to look at several E30s, that way you have several to compare against.
I looked at 4 E30s before I bought mine. I almost didn't consider looking at the one I ended up buying because it had 203k miles, but it was in the best shape of any I could find, and the mileage made a good bargaining point. The cars with the lowest mileage were in the worst shape (One only had 110k, but it was pretty beat up). I'm sure there are nice low-mileage cars out there though.