Tim at SDR is the best! He is known for his great customer service.
I have the SDR suspension on my desert race rhino, and it has been awesome. It works really great in the really rough stuff (I run the Fox remote res shocks). My buddy also runs the same kit on his 4 seat rhino.
As someone else mentioned, the kit used to be sold by Mason Motorsports. They moved on to bigger toys, and Tim took over selling the kit. Tim sold more Mason kits than any other single vendor, so he already had lots of experience with the kit. The arms are built by the same exact manufacturer as when Mason sold them, and Mason is still involved with designing new kits for SDR to sell.
Great kit! Great vendor.