The RDX is much quieter than my previous car, but I'd be interested in making it quieter. Has anyone done this? What areas did you concentrate on?

Most of the noise in our RDX is wind noise. This has been an issue for Honda/acura for many years (a trademark if you will) and I don't think you'll be able to get rid of it. Perhaps the best thing to do is just turn up the stereo.

In my previous vehicle I eliminated a lot of road noise by switching from Michelin tires to Continentals.