So here's where we are at with the S65 after a few months, and 5 weeks at the repair shop. Suspension still doesn't hold pressure overnight, but isn't leaking externally. Drives totally normal with no warnings during operation. So it's better, but looks kinda silly sitting on its tires overnight.
Here's what has been replaced:
-ABC pressure line, pump to separation point (8 hours labor, requires subframe to be dropped)
- front accumulator with pulsation damper
-front left strut assembly reman
-front right strut assembly reman
-power steering filter
-tandem pump reman (ABC and power steering)
-front lower ball joins
-untold quantities of mineral oil, but I know the system requires 10 liters
-12 attempts of rodeo test (system flush)
So its getting better, and I feel more confident driving it. Dynamic Seats still need more diagnosis, and of course the cluster blacklisting decided to quit (its usually a capacitor).
PSE pump looks fine, and the fuse was ok, so not sure what the deal with the seats is.
Had a random check engine light come on for Secondary Air pump. Naturally it went away when I washed the car a week later. 🤔
So I like the car, but I don't love it like I do the CL600. Will likely keep it a year and look for an SL next.