The dampers are probably at fault for some of the suspension issues, but I think there are other design problems too. Chassis flex. Poorly thought out angles. Bushing choices. I think somebody mentioned there's no subframe for suspension, which most cars will do in the rear, which usually has some big bushings. I'm not sure on that as I haven't looked closely. I just know that the car is unsettled easily.
The front is double wishbone, and the rear is multi-link. These are proven, reliable, solid design attributes. It does allow for design choices.
I'm not feeling chassis flex; in fact the construction seems solid, and the battery pack definitely doesn't flex much. I've raced Porsches, I know about chassis flex.
It's a very heavy vehicle, especially for it's wheelbase. Interestingly, it's 7% heavier, with a similar wheelbase to, the Lexus LS400 I had for many years.
The Lexus had air suspension, which rode extremely well but was expensive to fix when the dampers leaked - $1000 per corner....
As I see it, the MY design choice was for responsive handling, which includes a quick steering ratio.
It does that, but at the cost of ride suppleness.
I've put taller tires on smaller wheels (255/55/18) that have 1" more sidewall than 19" OEM, and gained a fair amount of ride smoothness.
But it still can get unsettled more easily than desired. I don't need a racecar, I need a boulevard cruiser with some spirit in reserve.
I've come to conclude that only replacement springs/dampers are capable of solving that equation.
I'm going to solicit some rides from people who have done the upgrade, then decide upon next steps, if any.
It's not too terrible, but can stand improvement. I still have just 700 miles on it (three weeks old).