promising idea.
When the weather gets warmer will look into it.
When the control arm bushing went bad on the chevy van, there was no question, just grab the spindle and jerk, no major effort required. These at least aren't that sloppy. But could explain the wandering it does on the freeway

Sounds like a bushing gone bad somewhere,it's fine throughout travel until the bushing cannot contain it then it pops and hit's metal/metal.

Suspension issues are hard to diag online,when involving noises that is.

Best bet is to look through the paper and find a place offering free alignment checks.
Part of checking the alignment includes finding any bad suspension parts,cause any of them being out of spec must be replaced before alignment can be done.
Alot could be found out by simply haveing someone drive the vehicle slowly while you walk next to it at full lock-should at least be able to narrow it down a bit.
Also try jacking up the front end and recreating the noise while looking at the suspension going from lock to lock.
It might not make the noise with suspension unloaded,which can tell you something also.

My friend had a Pontiac Grand Am which would make this noise when turning hard left or right from his front, passenger side.

The mechanic said it was his strut mount and that if you had someone stand there and look at it while you turn the wheel, you'd see the strut jump/turn. He said it really wasn't a big deal and it'd be more trouble to fix than it was worth.

but a grand marquis doesn't have struts. It has springs. and both ends are static (non rotating parts). One end is in the frame and the other on the control arm. The rotating parts are around the ball joints and bushings. It's a little different beast than struts.