jesseT: yes, the car has ball bearings. the stock chassis only accepts stick packs. im not sure if you can fit side by side packs if you use a dremel on the chassis, but i think ive heard someone try it. there is an aftermarket carbon fiber chassis, but i dont think its for saddle packs. the stock gear ratio is fixed because of a non-adjustable motor mount, im not sure what is the fastest motor that can make use of the existing gear ratio. but from what i read down the thread, theyre using 19T motor with great success.