Thanks for the replies!
Must say I love my car. That's why I am probing for improvements that will help make it unique, and improve performance. Since I am 56 yo I am pretty conservative about modding my stuff, not really willing to void my warranty at this point in time.
I had a reputable shop install the springs, and had to take it back once to get the rears in spec. They were able to get the alignment into factory spec (barely). No noises or nastiness, and the jiggly situation is not severe, but noticeable nonetheless.
To the suspension issue, would a custom shop be able to fit dampers not designed for this car? I imagine something like that would be possible. Honestly, it would be nice to have the ride height 1/2" taller (front) maybe keep the rear as is. I was initially looking at the Eibach springs, but was not able to source them so I went with the H&R. I wonder if I can find a competent shop to install some coil-overs from maybe a Mustang (??) or even a similar sized (big) performance car...
Any thoughts or collaboration is much appreciated! Thanks again... JC