I've noticed now that the weather has become gloomier and the ground is covered with a mix of powdered salt and rainwater that the Model S tends to kick up a lot of that grossness onto its own backside. Is this due to its aerodynamic shape or because there is no exhaust to "blow away" the ick? Next up on features: a protective bubble surrounding my car that protects it from the outside world (think hamster wheel) but until then, weekly car washes it is!