While there will be slight differences between brands of motors i think the biggest factor will be batteries and the driver.
Brushless ahs and will definately even the playing field.
Once Lipo becomes teh norm it will will come down to setup and driving .
casterracing EX-1 Pro, SP Silver Arrow
TOP Racing Scythe, SP 17.5, SP GT Pro 2.0
TOP Racing Scythe, SP 4.5 V2, Hobbywing Xerun 120SD 2.0
TOP Racing Scythe, SP 13.5, Hobbywing Xerun 120SD 2.0