Thanx Scooby. I installed it & my Monster runs great with the new filters. It sounds mean too, I love it. As far as improved performance, it is much smoother now throught out the power curve. However, that is with the TFI Box installed as well. So, it isn't a true representation of the filters alone. I definately would reccomend some sort of air/fuel mixture tweaking when installing any type of aftermarket air filter on your Monster. They come lean from the factory & with more air getting in it will run too lean if you don't make some fuel adjustments.