The Stage I sprocket set is designed to give you the maximum acceleration and increased thrust, WHITHOUT sacrificing top speed, AND allowing you to retain your stock length chain! And, you don't even have to break the chain or remove it to install this sprocket kit. (We will provide you with step by step install tips on how to accomplish this.) The Stage I kit lowers your final drive ratio about 10% through the sprocket sizes. So, that means, you will increase your rpm's by about 10%, reach your shift points much faster, accelerate much harder, and reach your top spped much quicker. Because the Stage I doesn't increase your rpm's so much that you will reach the revlimiter in top gear, your top speed won't be effected. And, in fact, when the rider weights 190+, the kit can actually increase your terminal velocity by allowing your engine to rev higher in top gear, creating more hp, and help overcome the natural rolling and wind resistances. The Stage II kit is approx. an 18% change and offers about the maximum amount of gearing change while using the stock chain length. This kit will move all your shift points up by about 2 gears. Unless you weight 200+, you can expect to see a compromise of 5-10% (10-15mph)in top speed.