What exactly do you want out of your buildup? If you want a race style truck, and have the coin, by all means hit up the Ground Pounder. It has just as much potential plus a lot of things that the Wheely King doesn't have out of the box.
Wheely Kings are fun yes, but like will said you need to spend some $$$ on it before you start dropping in BL motors and such. You would definitely want to flip the battery tray, get metal gears for the transmission, wheel wideners, stretched wheelbase, new shocks etc if you wanted it to handle well with brushless power.
That's why I employed Will to build my 14.8v BL TXT-1... IT has a lot of those things stock. Granted it's heavier and mucho more expensive, it will be just fine for my application. :ack