Idler Tensioner, Battery

Decided not to use the stock tensioner. Used the existing kit parts (as shown by sevoblast and others) to rig up a tensioner spring. Have no idea yet how strong or long the spring should be, but it's pretty stiff and I have even stiffer springs if needed. Also made up a new, longer cross axle.

Also added strips of aluminum U-channel to stiffen the bottom of the hull and to make a motor/gearbox stiffener frame.
I know I can buy all this stuff, but I have the tools to make it all, and I'd rather save the $'s for more external details.

Found a 6 x sub-C NiMH battery pack rated at 5000mAh. Is there a similar size higher capacity NiMH pack out there?

Thanks.