Got this thing with the hope that it would quiet down the Titanium 4 that was on my WR450 when I bought it. I might have dropped a decible or 2, but the pipe was still too darned loud. Later, I bought FMF's FS-Approved Spark Arrestor/Endcap for the T4. The combination of the two did not appreciably reduce the noise level, either.
GE M - February 22, 2014
(Coal Crk, CO)
The Core does exactly what it should...quiet the bike, so for that I give it a five star.