Yeah, I've got one - I like the sound with it uncorked, but my wife complained. When I first tried the silencer, I didn't think it helped at all, but I tried it again a few weeks later and found that it did indeed cut the exhaust sound down A LOT, to the point that my wife stopped harpin' on it.
Unfortunately, sticking that big plug in the exhaust stream (the exit pipe from the silencer is only 1.75 inches), while it deadens the sound also kills any power gain you got from the fatter pipe and unrestricted muffler in the system. I now leave it out, except on those rare occasions that I know my wife will be driving the car.