Although I plan to win the lottery later this year I am still going to buy used, just in case. I am fairly new to MF camera's. (I have little experience with a mamiya rb67 but that's all.) The hasselblad 500CM has been the dream for a while now but since it's a lot of money for a student I have some questions before I take the plunge.

-Are the 501CM or the 501C preferable, I read the differences aren't big but maybe I missed something?
-Are there points I have to pay special attention to when I am looking at a used model, I read the shutters are a weak point and some hasselblads start to leak light after a while but how can I check these things?
-How is the CB 2,8 80mm planar lens? (It's one wich is offered with teh camera very often.)
-Ohh and any other thing I should or might look at would be nice to know

Thanks for all advices/comments in advance.

cheers,
Quinten