is pipe wall thickness directly relative to overall sound of a bike. would putting on a pipeguard(carbon fiber) or a pipe made with a thicker guage steel(gnarly or dyno-port) make my bike quieter.
I have even seen people wrap their pipes with insulation for extra quietness. Also I have seen people wrap their silencers in old inner tubes...strange practices but they do seem to cut down the vibration tingy noises to almost nothing.