I was doing some reading over in the E550 section and I saw a few mentions of the cabin noise being louder in the CLS550 in comparison to the E550. A few people speculated it is due to the CLS frameless doors not keeping the windows as tight or maybe the larger rear tires. Do any of you notice the wind or tire noise in your CLS? How about in comparison to an E series? I'm leaning heavily toward getting the CLS but a quiet cabin is very important to me and my audio hobby.

In comfort suspension mode on 18in wheels this was arguably the quietest car I've ever been in.

Drive both and determine what suits you best

Thanks for the real world experience! Does comfort suspension mode change the exhaust and that is why it makes it quieter?

No exhaust change, suspension lifts higher so bumps are absorbed but also road/tire noise is reduced.

I don't own an E550 but do own an older (2008) E350 which is much louder than my '13 CLS550 on optional 19" AMG wheels w/Michelin Pilot Super Sport tires.

Oh, ok. That makes sense. It would increase in noise but probably not much. Definitely not enough to sway me off the CLS.

While not quite equal, it is still an example that an E series is probably not going to be any quieter than the CLS. I appreciate it!

Thanks for the input guys. I now need to hunt down the the right CLS.

I read somewhere a looong time ago that MB reduced the CLS glass thickness to actually increase the road sounds, as a result of owner requests to make it sound more “sporty”. I can’t find that reference anywhere now.
Has anyone else found/heard this factoid?

I think a lot depends on your wheels and tires on the car. Owner of both 14 CLS550 and 2021 E63S. Using comfort mode for both, on certain roads the E63s road noise is near deafening while the CLS550 is acceptable. On well paved roads, both are fine when I have the E63 in comfort mode and the CLS550 is sport mode. Difference here is the CLS rides on OEM 18s with all season tires ( rear OEM Conti, front Bridgestone RE980 ) whereas the E63 rides on OEM 20s with OEM Pirelli summer tires. I may switch the E63 to Michelin all seasons to get a quieter ride. This is just about road noise and I am not making a comment on exhaust noise where the E63 is designed to be louder from the factory.

Cls can tear thru tires because they are staggered. Tires can be louder when worn.

Does anyone rotate them from side to side at least to quiet them down?
When my tires would get loud on my Audis, I'd rotate them in a X pattern because they were square and they would always quiet down. If I rotated front to back only, they were still loud.

Mine only rotate one way so they'd have to be taken off the rim and switched.