I found some info about the various mufflers:
http://www.rconline.net/magazin-2001...iationen.shtml
From this, the silent muffler really costs a LOT of power. Unfortunately the 3243 pipe is not a lot quieter than the little stock muffler, but my, it does let 'er turn up!
Tests were on a .21 turning a "too large" 9x7 MA. I think the 1000 rpm loss of the silent muffler isn't worth it to me.
Jim