Hi guys- I just got the quiet core for the powercore4 exhaust that i have on my WR, and i should have gotten it a long time ago. even after repacking that pipe, it was obnoxiously loud. i don't have a sound meter, but just from the ear test, it was way more quiet. i haven't noticed any performance differences, but it was well worth it. you can buy it at the TT store. i got mine for $32 ,including shipping, and it was at my door in a couple of days. if you own this exhaust pipe, let's do ourselves (and everyone else) a favor and quiet things down. i'm going to write FMF a letter and ask them to include the core as part of the exhaust package. i know it won't do any good, but at least i'll feel good about myself. sorry for the rant, but i needed to let it out. i know that this has been discussed on the forum before, but i'm trying to make sure people know it's cool to have a quiet exhaust.