"The S-550 is a well built, quite riding luxury car. My AMG model has the same cruise characteristics - handling, wind noise, road noise, etc. - at 60MPH, 80MPH or 100MPH. But the 20" rims and specialty run flat tires are a disaster. Hard riding, expensive and no all-season styles are available. I rub of $100 worth of tread off on each Phoenix to LA round trip. And no spare."