that's 100% professional products spacer and throttle body, they're the only company that has that round adjustment ring for the TPS built into the top of the throttle body that i know of. i have a 90mm PP and it whistles when de-accelerating around 1400RPMs. i originally thought it was my Trick Flow manifold whistling and it may still be, but since i went supercharged, the whistle no longer bothers me that much