Keith is a good dude for sure. I do like the 20" but full disclosure, I went with the 20" to keep the noise down some since I was planning on headers. Basically I don't daily drive it and I like louder vehicles that sound good. I get plenty of compliments on it, especially at 5000 rpm's ripping around in the dirt.
One thing I can't remember if he uses as a selling point or not, but we did discuss this some. He uses a little thicker wall pipe and it changes the sound some, in a good way. I have only had a few small issues with the system, but nothing myself and a local fab buddy couldn't fix and I'm not exactly gentle to it.