Since I'm cheap, here's what I did.... I went to my local hardware store and got a 1 1/2 inch (the opening is 1 1/2 inch, the overall diameter is the same as the muffler) steel floor flange. The four holes line up with the stock bolt holes and it cost me $6.75. I thought about then putting a nipple and a 45 degree aiming it down a bit, but think I'm just gonna let it flow straight out the back. It opens it up a lot!