My Sig S has got 14,000 miles on the odo. It's a non-performance; air suspension; 19" wheels with original Goodyear all season tires. I believe the ride quality has been going south slowly for a while, now. It used to just absorb bumps with equanimity, without passing noise or vibration through to the passenger cabin, but lately it seems there's both more noise and less dampening: a more nervous ride, with some harshness that wasn't there originally, and a loss of grip when cornering in the presence of pavement imperfections. My tires are still in good shape with more than adequate tread, though they're due for rotation; tire pressure is the same 45psi I've always maintained. I suppose I may have been less sensitized to the suspension's quirks, coming as I did from an Acura RDX (which is known for its harsh ride quality), but I don't think so. Has anyone else sensed their air suspension's performance degrading with time? I'm not familiar with the air suspension's inner workings: what parts of the system might account for this? I've got a service appointment coming up for my 12-month inspection and I'd like to have some more ammo when I talk to Tesla about the problem.