I can easily see the logic of upgrading from a 28-tooth to a 29 or 30-tooth sprocket to lower rpms and save a bit of fuel. However, before making the decision to do so, I wanted to know two things: (1) My Spyder RT-S PE (391) is brand new and I've not driven it at high speed on the highway. Need to get an impression of that to see if it's what I really want to do. (2) I wanted to see what BRP had to say about it; both techinically and with regard to warranty. I sent tech support an e-mail and was answered telephonically the next day by "Carlo" who said he couldn't offer an opinon technically or regarding performance. Regarding warranty, he said the Spyder Warranty covers defects on the bike, and whilst the aftermarket sprocket doesn't void the warranty, the warranty would not cover any damages brought about from using it or breaking something while putting it on. Makes sense. So that leads me to my next question. (4) Is there a how-to on how to do the upgrade? ... and finally, (5) has anyone done this upgrade on an SE5? Thanxx :spyder: