I installed the MRW kit to some wheels a few years ago. I liked the kit because it is a lot lighter than most of the add-on kits, and included nutserts for the inner ring so no messing with nuts and lock washers.
My buddy installed a common 1/4" ring kit on his wheels at the same time. The install was basically the same (as far as welding the rings), but assembling the wheels was way easier on mine than his. The MRW kit is generally a lot more expensive than other DIY kits, but I picked mine up from a guy on ebay for about $250 which was a great price.