I've just gotta say, when I first installed mine I was skeptical coming from the turbosmart kompact BOV, especially because I wasn't used to how damn quiet the stock BOV is. This does not make it louder, but after having it on the car for a few weeks I can absolutely confirm that it holds boost more consistently and lets the turbo spool much smoother, particularly when heel-toeing and shifting quickly. It's not a night and day difference, but it's subtle in a very, very good way.