Unfortunately the cheap motors on ebay don't quote the gearbox ratio so that doesn't help much.
They quote the motor voltage and output speed and the ones I bought were 6V 300 rpm.
I will post a video in my controller section so you can judge the speed when running on 2 lithium cells.
Its very difficult keeping track of these discussions when you keep changeing topics why dont you have your own topic under questions and answers.
The controller prices do not include the receiver and if you are buying the 4 chan hobby king receiver you would be better with the newer hobby king compatible unit.
Although this is £3 dearer than the D option board it has twice the current drive to the motors and is smaller and lighter overall. http://i109.photobucket.com/albums/n66/ ... MG1259.jpg http://i109.photobucket.com/albums/n66/ ... MG0722.jpg
I haven't updated the web site with the new controller yet and I just call it the HK4 controller.
ie. compatible with the Hobby King 4 channel receiver.