Guessing it's pretty much just an easy slide on, on to the stock rail of the KSG? Thanks for all the feedback so far!I use the extended lower rail by Hi-Tech Custom Concepts http://www.hitechcc.com/product/HTC-107X.html
They also have a non-extended rail, both the same price. I like having the extra inch, and also think it looks better aesthetically on my KSG, but that's because I have the Howitzer muzzle break sticking out.
Quality seems top-notch to me. No issues whatsoever adding attachments. I've been very happy with it.