Well left for the UP happy with my viper, and returned even happier with a 05 warrior. 6mpg to 16.5 mpg and no oil, and the warrior stock was as fast if not faster than the viper. I never thought a stock sled would impress me, but this one does it. Viper Daves stock 06 attack was just as impressive to me. I'll still lurk around, but gone 4 stroke for now. Maxdlx