If you fellows want to replace engine parts later on down the road, go ahead and buy those "quiet mufflers". Do you remember the movies where a teenager puts a banana or potato up the exhaust pipe of a car and when the owner of the car starts the engine-bang! Well, it's not that extreme but it's close. Those silencers are so restrictive that your engine will suffer from overheating, due to too much backpressure. That's how those things quiet the exhaust notes. If you have a carbureted atv, the jetting will be off and you may suffer from a too rich condition which will contribute to a hot engine and increased wear on the rings, piston and valves. Most utility atv's are so quiet now that putting one of those on really won't make any difference. Don't believe their claims of no decrease in horsepower. Most of those claims are taken from the horsepower readings taken just above idle speed. I can almost guarantee that your atv will feel sluggish at any speeds above 1/4 throttle. If you feel that you need a quieter method of transportation-just walk in. If you use the many trails that are available to atv's, the animals are so used to those sounds that they won't be spooked by your atv's exhaust note.By the way, I've been a motorcycle mechanic now for over 15 years. Save your money for some hunting accessories.