I got a look at a Pro Moto Billet insert for the '05 pipe. My question is why not just take out the stock insert completely and just leave in the spark arrestor? I did this a week ago and my bike was still relatively quiet while riding around the neighborhood. it didn't seem to make any real significant power gain that was noticeable; but has anyone done a dyno test with the stock insert removed? Am I missing somethin' in this whole equation?