it made a difference for me. I had a invida test pipe with my greddy ti-c, sounded great but once in vtec it had a little raspy buzz, nothing horrible but i didnt like it. Got a megan resonated test pipe off ebay and slapped it on and no more buzz, still sounds like it has a test pipe but no raspy-ness

 

rattle rattle

 

does it make the hallow sound like normal test pipes? i have stock exhaust and ive seen videos where they accelerate and the car makes a nasty hallow sound. will it give me a nice smooth sound or just make my car sound raspy??