While you can customize one of these little guys, you cant change any kind of oils out on these guys. They have a worm gear setup for axles, and the real benefit of worm gear is you dont need a drag brake. These also use a ESC and Reciever combo. If you want to switch out to better motors and servos, you have to find really small eletronics. I used a little hobbyking 18amp esc, tiny outrunner motor and a hitec servo in mine.

Its also pretty easy to create custom lengths on the upper and lower links, along with lengthening the drive shaft. The body of a bic pen will work as a drive shaft. As far as that trail trekker in the video, hes running mini qlow tires, along with custom wheels and a widener kit. Its really hard to tell from that video, but the mini qlow tires are huge compared to the stock tires, so you have to run different rims, a widener kit, high torque servo, and a powerful motor. I also may be mistaken but the one company making a aluminum widener kit stopped making them. They only one you can get currently is made of delerin and that was a couple of years ago.