I recently sold my 2010 Pro4x for a 2013. Only mods done to the 2013 is a BDGT, K&N CAI and bilstien 5100s. I am wanting to get a deeper exhaust tone, but don't want to get much cis or drone. My questions is which one would be the better choice for both sound and performance. I don't want to spend the extra money for the cat back if there is not much difference between it and just the muffler swap.