I gravely miscalculated how much cargo space I'm giving up. Not just all the little cubbies that the m5 had (Where I had the fire extinguisher and the first aid kit) but the fact that the read door slopes inward, such that even thought the measurement to the back of the seat is almost the same, the drum space is greatly reduced.
Now, I don't know if my future contains a car packed with drums very often, but this realization started to make me cry. So yeah, regret already.
Oh yeah, I bought the c-max.