There is a tutorial about how to do this over on URC I believe, requires a mill I believe though (Or a drill press with the correct size of endmill). From what I've read it seems like everyone has had good results, no strength problems. Not sure if the same can be done with Maxx RPM knuckles though, I'm assuming you want to do something like this to your truggy-maxx Kcaz?
More info here, scroll down and they show a 16mm drill bit modified to drill out the bearing holes for standard 8x16 bearings.
http://csgbenefits.org/mgt/MGT-RPM_Knuck_Mod.htm