I think with high power handling subs, cast baskets are used to avoid "rippling" the basket at resonance frequencies, which can cause misalignment of the coil and motor slightly. I dont know how that affect the woofers though. I've never heard of a motor twisting so bad that the coil started to rub. It may be more of a sound quality thing, but I'm not too sure.
As far as cast baskets go, I've seen some on youtube break spokes.