I found biochemistry to be a big help, because it forced me to incorporate many things from my LS classes and from chemistry. The information was okay, but the thinking was really helpful.
Physiology was the only school class that I think was an absolute must. You need time to digest that material, and a four month MCAT review might not be enough.
I like Coffee's suggestion of paralleling a review book while taking the classes, although having used EK and a few other books (I spent so much money and time, 🙁 ), I'd suggest BR books. They're a little more detailed which would help with the classes more. They also have great tricks that EK lacks.