same drop, B's are progressive and C's are linear in spring rates, Hence B's are less harsh than C's. I believe that B's were used on Bullitt cars. They had Tokico shocks on them though.
I think the general wisdom is that B's are so close to stock there's not much reason to swap. I know I didn't feel any difference, and the drop was minimal compared to my stock height on worn-out springs. So I couldn't say that B's are worth it myself. If your goal is either dropping or stiffening, I think you should go beyond a B. Am I wrong here?
I've got B's and they dropped the front about an 1 1/2" the rear about 3/4". Compared to the worn out stock springs and shocks the ride is alot better. I also went with tockico blue shocks at the same time. I an currently running 18" wheels and I'd say it rides damn good...