It seems like there's a lot of really good exhausts out there. I just have one question. How come some of them have only one pipe exiting the muffler and some have two? Seems like you'd get more air flow out of there with two. So why have one? I'm only asking because it seems like I like the sound of the ones with one pipe better than the ones with two. (ex. Roush/ MBRP) I just want to make sure I wont be missing out on more power or something.