I like how the new SU/Turbosmart bypass valve sounds. Nothing too crazy, but louder than stock. And an easy swap that will do what the car expects it to.
The Turbosmart sounds like whiplash. I love it! lol. The greddy sounds great too tho. IMHO I didn't really care for the TXS Hybrid I had. It sounded to "airy/whooshy" to me.