Hey gang, For those of you interested, I just got done running some crude sound measurements on my 05 WR450 exhaust. Environment: Cold(35°F), damp, overcast, 15 mph breaze, open field (nearest building 75ft). I used a calibrated B&K sound analyzer "mediator 2238" This is not a cheap radio shack model, we are talking a $5k machine I borrowed from work . As far as professional analyzers go it's still the bottom of the line . All tests were performed per the SAE J1287 standard. Results: No insert, No SA, No tail cone/cover WIDE OPEN CAN = 100 to 100.5 Db No insert, SA installed, tail cone/cover installed = 96.5 Db No, insert, No SA, Just cap/cone installed = 97.8 Db "modified insert", SA installed, tail cone/cover installed = 94 to 94.5 Db This is a link to what my cone shaped "modified insert" looks like. http://img.photobucket.com/albums/v610/trailriderjoe/IMG_0846.jpg Thoughts?