It's a nice car, well worth it for the fun. It's not as fast as many other new models, but it has a certain 'feel' to it that many newer cars don't have (might be worn ball joints:D). It isn't as refined as newer cars, and it's not very powerful either. If you're not 100% sure about it, sell it. I'm glad you decided to post it here. I'd bet most of the M42s here were bought off CL.
I agree with you about the touring...I'd absolutely get one just for the novelty. I'm not sure how I'd feel about a few hundred pounds of wagon on the rear end.
It's also likely that BMW will never make another car like this one...like the 2002, it'll never happen again. Might never be a collector's car, but it's been worth every penny to me.