From a Yoshimura press release:
Yoshimura knows the YamahaYZF-R1. With feed back from racers around the world including the Westby Yamalube team, we have built a masterpiece Alpha-T 3/4 race system that makes the new 998cc Yamaha R1 come alive! As soon as you install our new AlphaT 3/4 race system you will notice the one of a kind sound that the Yamaha crossplane engine and Yoshimuras Alpha T muffler make – pure music!
Peak horsepower is up almost 5HP and peak torque is improved by almost 5lbs. with the new Alpha T 3/4 system. Great weight savings are realized as well: Over 12 pounds less than stock with the Alpha-T 3/4 Ti system!
The all-new Alpha-T comes complete with a carbon fiber heat shield, and available in either stainless steel or titanium Works Finish. Proudly made in the USA!
2015-16 Yamaha R1 Race Alpha-T 3QTR SS/SS/CF WF