Just as a point to note-I have one of these things on my FiST and it is absolutely one of my favorite mods. It does absolutely nothing to help (or hurt) performance, but I love having the boost vent to atmosphere. I park in a mult-story garage for work, and the sound of the boost slowly bleeding off even after small throttle openings is great fun. I always roll down my window to hear it. I think it gives our cars tons of character.