I've got the supertrapps (same thing). Bought from someone on this board (though not Craig) who also found them too loud. I don't mind the sound much. Better than stock but not as smooth or pleasing as others. Need occaisional repacking to keep em sounding nice. I've tried different numbers of discs with no noticeable change in sound or performance. I'll probably switch to FMFs when time ($$) is right.
FMFs also have approved spark-arrestor, sound better, and are cheaper (new). In a nutshell, get the FMFs.
'04 525EXC D/S
Will herd cats for beer
(... but I rescue puppies