Curious what others think about the ride quality on the 2018 e400 with a STANDARD suspension. Many of the reviews and information out there are focused on an those with the air body control suspension. However, those are difficult to find and mean making other sacrifices in terms of color, options, etc.

Unfortunately, the roads, even the interstates in my neck of the woods are pretty rough.

I realize each person's "seat test" is somewhat subjective - but am really hoping this thing rides more like a land yacht and less like C63 or other sport sedan.

Define "land yacht" as that is also highly subjective. If you mean that completely disconnected from the road "floaty-type" feeling of an old Caddie or Lincoln, then no. That is what MB airmatic systems try to replicate, but with better overall handling. If you simply mean much softer than the performance tuned suspension on an AMG C63 or any other performance sports sedan, then yes. The only way you're going to know if the standard suspension is acceptable to you, is for you to road test a vehicle with the same type suspension. Any MB dealership will have some MB model on their lot with the same suspension as in a standard suspension E400. No big deal to setup a test drive to get idea of the road feel of the standard suspension, if the dealer knows you'll be ordering a E400 coupe or cabrio.

I don't mind the ride quality. I'm not in love with the tires though. I think changing out the run flats would make the ride quality ideal.

Yes, definitely get rid of those run flats. Makes a big difference in ride quality.

I would think that if the roads in your area are rough you would want the airmatic suspension. I find the ride in my E400 with airmatic to be super under all road conditions. And then you have the advantage of adjustability i.e. comfort, sport and sport plus. Bottom line; drive and compare both before committing.
Good luck with your search.

AGREE with pdeacon - I have an '18E400 Cab with the Airmatic and the ride is superb - and obviously can be tailored to both the road conditions and your desired driving style in the moment. It is a cost trade-off to seriously consider.
Good luck,
Steve

Couldn't agree more!

Review for the E-Class Convertible with the standard suspension. The reviewer goes into details about Standard vs. Air... commentary about suspensions starts around 26:20. Link-
He also got another review video with the E400 Coupe with Air suspension where he talks about merits/demerits compared to the regular suspension... commentary about suspensions starts around 25:50. Link-
Personally I chose the E400 without Air Body Control to reduce the price of the car, and I felt it was a bit more connected/sportier without ABC. Car gets build sometime in February and is available for pick-up in April

Enjoy the reviews.