Just completed 2500 mile r/t, DFW to Bradenton, FL, on a well-broken-in LR MY Dual Motor (5k miles). MOST of the ride was wonderfully smooth, easy, on newer asphalt/concrete. Even older asphalt.
On I20, through Shreveport, it was sometimes terrifying, like driving too fast off-road. The car was airborne at times, even at 55-60mph. Thankfully, no cabin rattles, thumps, clunks, nothing fell off. I was impressed the interior didn't start falling apart.
I'm now even MORE impatient for the MPP Coilover kit. I don't expect it to tame the (dangerous) rough concrete in Shreveport, but I"m looking forward to significant improvement in my region. Some of the roughest concrete here is within 3-4 miles of the suspension installer, so he'll have adequate access to testing and dialing in the suspension.
Now...about the cabin noise...It's deafening at times, on rough aggregate surfaces. My ears will need a day or two to recover. I will be exploring sound-deadening solutions, although I know (there's a very thorough thread here) the results my be limited.
LOVE the car: HVAC was flawless, seat very comfortable, tracks perfectly (even after 2 drives through Shreveport!!HAHA) , handles well. Cruise control? A bit tricky to control when passing slower cars, as it wants to decelerate first (engine braking) , then lunges. As with any new car, it's a modest learning curve, but otherwise, an extremely satisfying drive. Stopping every 110-180 miles was perfect for me, and my energized MiniAussie. Frequent breaks made for an easy (each way) 27 hour trip, w/o hotel. Catnaps sufficed.