The larger the muffler pipes, the more sound will pass through with the power wave. Big pipes make more sound. We can absorb a certain amount of this sound by utilizing a longer muffler, but at some point this becomes both expensive and heavy. We often use XR-1® mufflers that are over 30" long for serious, Pro off-road trucks. This is double the length of our popular street car mufflers and almost three times longer than, say, a Corvette S-style system. Trophy trucks have no requirement regarding mufflers, but almost everyone runs them. In fact, every Baja winner and SCORE off-road race winner and champion for the last three years has run BORLA’s. We pay no contingency, and these teams spend millions on their efforts. It is the F-1 of off road. Most teams have $250,000 chase trucks and several 18 wheelers as well as one or two helicopters for these races. They don't want to give up power, but they want to hear the radios. They also say after a horrific Baja 1000 they feel twice as refreshed after the race with the BORLA mufflers on. In fact Alan Pflueger, the flyin Hawaiian, drove his Monster Energy Drink Trophy Truck the entire Baja my himself and credits a portion of that to the quieter mufflers we built for him.