basically it is all about the midpipe. 4 cats kill the sound. you can't make your car loud if you wanted too. if you are keeping the stock go with the 2 chamber you will need it. if you ditch the stock one there is going to be a point were some poeple don't like the drone from the 2 chambers. I don't like flows becaue they are not stainless. If I were you I would look at the borla stinger or magnapacks. stainless is the only way to go IMO.