Now that I own both an Audi S6 and a Mercedes S63, I can honestly tell you that the Mercedes is so much quieter on the road.

Both cars have 20" wheels and very new Michelin Pilot Sport 4S tires on them. The Merc is probably 20 dB less road noise on the highway. The engine noise is louder than the road.



The Audi always has this tire hum on the highway. So annoying. It is highly unlikely that my next car would be an Audi. I'm probably going back to BMW after the S6.