I just got the retrofit done a few days ago on my early build car, its a nice difference.
Before it was noticeably stiff, most bumps were uncomfortable, especially in the back seat. Freeway expansion joints bounced the car, I would cringe over bigger bumps.
After a couple hundred miles on the new setup I don't really notice the suspension one way or another....and thats a good thing! It just works.
Handling is still stable and solid, low center of gravity etc... The newer suspension feels like a much better handling/ride compromise.
For a point of reference my last 2 cars prior to my Tesla S and 3 were BMW 3 series coupes.