Greddy exhaust systems have a nice sound. I have the PE, which is probably a little louder than the SP; but the PE is a lot better for a TT since it has bigger piping. I used to drive my friend's late model v8 firebird w/ flowmasters and it would give me a headache. But my Greddy exhaust is not bad at all, there's no bad resonance just a nice mellow sound that gets louder with RPM, or a little louder permanently w/ test pipes. You can buy the Greddy EVO now since they stopped making the PE, but its basically the same thing.