Speed 900 sized motors are virtually impossible to get hold of unless you buy the Caldercraft 900's which just don't have the power of a true speed 900. I think brushless drive could be a viable thing for the future, Mr Mangle proved it can be done successfully and for a cheapish, powerful drive system with easily obtainable spares that can fit into tight spaces i don't see a comparison, i'm personally looking forward to seeing what Matt and Mario come up with.