I have a '99 GT Convertible with a few bolt on mods (CAI, pulleys, TB, O/R h-pipe, Magnaflows) and a custom dyno tune. The car runs great but the engine seems louder than it should. What I am hearing is "airy" sounding, especially at low speeds/low rpms when it doesn't downshift to 2nd gear. I am wondering if it could be an exhaust leak at the manifold. Or is the 4.6L just noisy in general?