I dont know if it is a length or quality thing when it comes to the aftermarket (rebuilt) CV's. I do know that if you have done anything on your lift that allows it to drop further than just installing the strut spacer that you will have the over extending issue. So you dont trash another, when you get your replacement, peel back the boot after installing it and cycle your suspension with a floor jack/jack stands and see how if the bearings are hitting the retaining ring. If so, you may want to consider making a spacer out of one of your busted cv's by cutting the cup off and grinding it down to fit. This will give you another 1/2" or so.
Zig