I'm using one of the mega's with the GD600 box in a sport-e-stick and it works fine. The only problem is that you can only go down to a 13 tooth pinion due to the large (5mm) shaft on that motor, so the gear ratio is not high enough to swing a really large prop. I'm turning a 12X8 with that setup on the stik. There is a "new" firewall for the E3D that allows both the GD600 or the MEC superbox to be bolted right on without modifications. That's been in the kits since around last august.