i wouldnt worry too much, UCAs on miatas dont hold any weight, they're really just there to hold alignment figuresBumping a dead thread...I'm about to try the fronts. Let's see if they're any better than the rears.
On the plus side - doesn't look to be any serious possibly failure points except the adjustable camber part and the bearings there.
Will be torture testing the crap out of them that's for sure.