I just put on my Craford cast plenum to finish up this set of mods for my 6MT sedan. Here's a nice bonus; there is almost no sound increase except at WOT. At part throttle; these mods make no noticable sound difference. I already had a Stillen intake and Z tube on the car; and that made a more noticable change to the sound levels; but still mostly at WOT. The sound is great when you open it up, and there is noticably more power, especially at upper RPMs. Since there is no change in sound at cruising speeds, this will be a very easy set of mods to live with. My only problem is the grin factor...I keep standing on it, and my milage is down to 12.5, (I'm usually at 16.5. I drive mostly around town and generally drive pretty agressively. I've seen high 20's in this car, but only on long trips.)