I would check to be sure the springs are seated properly.
Some other people on TR have lowered cars too far
to the point that the springs flop around and make noises,
sometimes rubbing against the side of the shock....

I would check to be sure all the rubber seats are in place.
Some people leave them out and the springs rub against the
seats as they are compressing/decompressing....

Understand that as a coil compresses, it rotates slightly, and
leaving out the rubber sometimes makes noise....some MFG's
will have one or more bearings at the top of the spring that allows the
shock to rotate quietly....if the bearing is not sealed, it needs
clean lubrication....

When people have brought their cars to me, those are things I have found. Picky as I am, when I install for other people,
I even seat the spring in the exact spot it was previously installed
in, as it makes a better seat.-Bob