The Rossier pipe really wakes up the fuel injected YFZ. We saw an increase in the peak power from 34+ to an honest 43+ when combined with the Rossier cold air kit (we run heavy dyno tires). It also completely eliminates the stock sag at 3800 RPM that is present with the stock pipe. Couple that with the ability to rev all the way to 10,000 rather than nosing over at 8500, and you can see we have a killer pipe here. The large diameter head pipe also works very well with our big bore and stroker engines. Dyno charts coming soon.