I've got one on my 220 and love it so far, although I've only got a couple hundred miles on it. Have not changed packing yet, but the S/A is not as quit as I was expecting. I'm running it with the rev pipe that I have had on there for years, and can't hear any Db drop from my old blown out stock S/A. Have not had any Db measurements taken though, so I'm not sure exactly how loud it is.
I do not have any pictures to post, but it looks good on the bike. Pretty long unit though, almost touches the rear fender.
I ride a 02 RM250 with a turbine core II and my buddy has an 03 with the Q and unless you have a DB meter you couldn't tell a difference sound wise. I don't like how far the Q sticks up.... assuming the KDX would be similar.