Your post raises some interesting issues. it's a bit amazing that people complain about ride with 18s - we have the 20s with a heavier wheel, almost no sidewall, and the car seems to ride really well, all things considered, except over really sharp impacts. However, we did improve all that by dropping some unsprung weight by going to aftermarket 20X9 wheels that were at least a bit better over really rough roads. However, I wonder if your experience raises the possibility that the early models had a different suspension bushing formulation or less isolation, or some other parameter that they changed out early on. Have you ridden in a more recent M3 with 20s? If that cars rides better than your car, I would have to wonder if they did something unannounced with tuning of bushing firmness? Some early road tests also commented on the harsh ride as well, again, quite at odds with how our two cars behave. Also, the Pilot Sport 4S on the DMP+ rides amazingly well considering how well it handles. What tire came on the 18 inch aero wheels? Probably one of the MXM variants? Did you have a Telsa service person ride with you or drive to get their feedback?