Snowmobiles have historically been powered by two-stroke engines, which provide generous power. Problem is, they’re also generous with noise and pollution. Cleaner four-stroke snowmobiles appeared on the market two years ago, and while they offered blissful silence, reduced emissions, and excellent gas mileage, they simply didn’t have enough punch to entice true enthusiasts. This year, Yamaha’s RX-1 Mountain promises to change that. With a 998cc, 20-valve four-cylinder engine derived from the much-heralded R1 racing motorcycle, the RX-1 packs a 145-horsepower wallop, enough for even the most jaded horsepower junkie. And with 11.5 inches of rear suspension travel, and a narrow, 38.6-inch ski stance, the RX-1 boasts catlike agility to match its catlike purr. $9,149. (800) 962-7926,