I run the one that pokes back into the muffler the farthest, and allows me to use the spark arrestor. I have good torque, although I also run a power commander. To me all the benefit of the muffler is no cat, so it is cooler, and lighter. I live in AZ so a spark arrestor is a must, and I want it to be as quiet as possible. Do you notice any performance different with the various inserts?