Depending on what arms your running (RPM vs stock), you may run into issues of snapping shock shafts with alloy ball ends. That's what I ran into with mine. RPM arms have 3 holes in them I believe. I was running P2's and had the shocks mounted in the holes closest to center for the tallest setting. When you land flat, it was fine, but if you land hard off kilter, it would actually jam the rocker against the end of the shock body and snap the shaft right off.
I've been running my current revo all summer long (probably about 3 gallons of fuel so far, BB) with rpm arms, nice teflon/anno'd platinum shocks. I've replaced 4 ends so far, all of which on the rear (just did 2 tonight). They get deformed from hitting big air. I have yet to rip one off.
Also, I run a side pipe, which keeps some of the direct heat from the shock ends. That's what was believed to be the issue with stock trucks with the pipe sitting right over them like a broiler making them soft and they would rip apart.
I've found running in the middle hole on RPM arms gives the best results with two things, shock ends and axle carriers. At the tallest setting, I also had an issue with the pillow balls popping through the carriers. In the center hole, that's far less likely to happen. Now that I run tru-track on this revo, the rears won't pop out regardless what I do and I'm still running stock front carriers.
Also, if they are ripping off the threads, you may be over tightening them, which is stripping them a bit making the threads weak from the start. You just want to tighten them until the base of the end hits the flat spot of the shaft. Then a hair more to keep them snug.