Tuned pipes suck for 3D. The stock muffler or a beer bottle pipe are much better. The macs one piece muffler is somewhere in-between. I have a macs one-piece muffler on my 55AX and 160FX and it's good. It did make the midrange a little burbley but not bad. The high end got a little boost. The big benefit of the one-piece muffler is the weight savings (2.2oz on the 55AX and 6.2 oz. on the 160FX) over the stock muffler.