If you truly want "quiet" and not just "less loud" then you can't beat the Legsport muffler plus a resonator in the midpipe:
http://www.ft86club.com/forums/showthread.php?t=83973
Even with headers and a resonator less cat pipe, my legsport muffler is extremely quiet. Reason being it has TWO mufflers in sequence which you can combine with a midpipe resonator for much quietness!