So the TOP axle pin holders are a direct fit on the 416. Basically, rather than use a setscrew to hold the cross pin in a CVD, this sleeve slides over it and holds everything together. It eliminates issues with pins coming loose, or setscrews backing out, stripping, etc. The only thing you have to be mindful of is that they increase the diameter of the axle ever so slightly, so you want to be careful none of the screws from your ball studs (or coming through the bottom of the steering block) are too long.
In addition to the reduced maintenance, they seem to free up the CVD's in the front a bit as well.
http://www.amainhobbies.com/product_...der-Titanium-4