Random but violent front end vibration

Did you install new upper control-arm cam-bolts?
If yes, my experience with those is that the new ones do NOT have enough threads on them to properly clamp the bushings. I ran into this a number of times with customer cars.
The solution is to grab a handful of thick hard washers and put one on each end of the new bolts, making sure the Eccentric washers still have enough engagement, then bolting it all back together, and resetting the alignment.
If there is Not enough Eccentric engagement, then put both washers on the nut side.

The first time I ran across this, I was backing a car off the 4-Post drive-on lift, and when I hit the brakes I heard a hard clunk, which I knew shouldn't be there. So I drove her back on, and as soon as I hit the brakes, there it was again. A little detective work found that the Upper Control arms were almost Loose. I put the wrenches on them, and they were tight as could be, which led to the discovery of the not-enough-threads.
After that I kept an eye on supplier's bolts, and every one had the same problem.
Here's the deal;
when the control arm moves, it takes the caster with it. When the caster changes, so does the camber. When the camber changes it yanks the toe-setting way out, and then the car becomes unstable, steering itself. When that happens, so does the "death-wobble" .
If I'm right, the fix is cheap and easy.