SOWNARE: Try this site for some in-depth testing results on motors and he sellsGraupners that he had tested also: http://www.customrcmodels.com/M5Stuart/id73.htm.

I've made some good progress with mine. The repairs seem to be holding just fine. I have been thinking about belt drives (industrial nylon belts and pullies) and new motors. First, It would really cut back on the gear noise, and the nylon belt and pully system will outlast the metal gears. You never have to lubricate the kind of system I'm looking at: http://www.intechpower.com/Pulleys_and_Sprockets.html

They are rated for high speed start and stop industrial systems. I think this would be much cheaper than going to specially fabricated nylon gearboxes. This is a project for over the winter, so I'm not very far along with it.

High torque low rpm motors would reduce the need for elaborate gear reduction systems. There is a motor I saw that is 600 rpm. Just have to figure out what the drive wheel rpm needs to be to scale out at about 43 mph which the Stewie was said to achieve. I think thats about 7 mph at scale.

Mine kept throwing a track everytime I drove it, but I discovered that if I raised the idler wheel up, compressing the spring just a little, the track tightened up a bit. So, I blocked the idler up about 1/4 inch in the suspension. So far, no more track throws.

I just bought a NIB Stewie, should be here in about a week or so. I may part it out, or maybe convert it to the above mentioned system.
Good luck with yours