A true dual like what you currently have will never sound good due to the back pressure. You need some sort of H or X pipe in there. I know this isn't finished and you have a few kinks to work out but you will get it how you like it.

Bobs exhaust sound really good now. He swapped in a two chamber flowmaster stainless steel race muffler in place of the MBRP muffler. His is all 3 inch stainless from the cat back.