I put this on my Evo 2x w/ Active 50, power pipe and performance air filter. It is the perfect upgrade, really balanced it out. 1st gear is now useful for more than ripping skids and wheelies. It can still climb a steep hill decently well with me on it (135 lb) and top speed on 2nd gear now pulls my eyeballs back into my face.
If you have the power pipe and active 50 this sprocket will balance your scooter out well, and I'd highly recommend it. Installation instructions are under "Evo 2x Shop Manual", search and there's a PDF of it available.