Love the look of these exhausts. So they only really sound loud when you give it beans?? I was looking into having a butterfly valve put in by an exhaust company by me in a few months. So with a touch of a button it opens and acts as a full through. How much would you charge for the r32 style rear just the cat back system. And then how much fr the additional sports cat. I've got the r32 bumper just need repair and paint.