Hello Gents....2015 Road King, my question has to do with Stage 1. With the Cat stopping everything up is it prudent to add a HF air filter and a tuner? I already have a set of Rush Big Louie slipons that sound pretty good after I unwrapped the baffles. A guy at rush said as long as the cats are present that you can open it up as much as you want but it can't breathe out sufficiently. He suggested true duals or a pre-2010 head pipe (or cutting the cat out). Opinions on this? Thanks in advance.