More suspension lift means higher CV angles. The more CV angle, the more likely they are to break. If you disassemble a CV you can see the cage that holds the balls in place is weakest on the edge, when you get high CV angles it places pressure on these weaker area's which break easier. The straighter the CV joint is, the stronger it is, because of increased amount of metal in the center (area under pressure). To reduce the CV angles we drop the diff down lower and in turn reduce the clearance that the lift created.
High pressure at high CV angles will almost always find relief. OME struts at 2" longer by themselves do not usually cause a problem. Strut mount flips, or strut spacers by themselves do not usually cause problems. Put any two of the three together and it does not take much force to break the CV's. I have broke two CV's climbing up with one side (allowing the other side to drop lower than normal running) and very little force on the CV that broke.
And yet there are some who have 3+" of lift who have not broken their CV's.