I have the Nitro Sport and the exhaust consists of the small metal pipe off the motor that connects to the rubber exhaust pipe then connects to the actual muffler. A what seems to be larger aluminum pipe is offered to replace the smaller stock pipe from the motor and also a tuned aluminum muffler is offered to replace the stock plastic one. I was wondering if these upgrades really add power or are they just nicer looking and a waste of money. Thanks.