i've got the novak gtb brushless with their 10.5 motor in my genX and it's been flawless. It works great with 4cells (and no reciever pack is necessary), and I'm very happy with mine. A few guys at our track have chosen other brands (mostly LRP or speed passion) and some have had frustrating teething problems or compatability issues. By contrast, my novak system (emphasis on the word system) works perfectly and is plenty fast. I've had none of the shut-down or radio compatibility issues that I've seen others suffer with. The other speedos (especially the speed passion) do seem to have more adjustments available but I've not had any trouble finding a good setup and driveability with my novak. For a simple to use, and ultra reliable plug and play brushless system, I'd say that the Novak setup is an excellent choice. And it sure doesn't hurt either that the pricing on their combo package is very reasonable. Just be ready to put a huge rollout in the car. Mine seems to like about 60mm on a fairly large carpet track. Even with this huge gear it's still nowhere near the heat limitation that's called out in the instructions. But it is geared way higher than they suggest. The motors don't have big RPM but they have so much torque that they can easily pull most any gear that will fit in a 1/12th scale car.