I know I am just a stupid person but I just took the vacuum line off my bike and it sucked! No power at all, it wouldn't even pop a wheely, there was no throttle response and it was very laggy, I pulled over and plugged it back in and pulled a wheely leaving the parking lot and had tons of power. It must give the bike way to much air on the bottom end or something. I always open up the air box up on everything I own, I like everything to get lots of air, but this mod went backwards!!! As for noise there was no difference, just a lot less power.