I find the Santa Cruz to compare very well to the CX-5 in terms of wind and road noise. It's early days with it but over this past weekend I took it for a 2 hour drive on a mix of highway and back roads and was very impressed with how quite the interior is. Mine came with the 18" tires and I don't hear much road noise at all.
I don't have any experience with the CX-5, but you did inspire my curiosity a little bit...
I used a decibel meter on my iPhone (
Decibel) to create some data points in my Limited.
Interior, engine stopped: 32 dB
Interior, engine running (stationary): 49 dB
Interior, moving 30 mph: 63 dB
Interior, moving 65 mph: 68 dB
It was a raining, but the air was still. I do notice when the air is thicker and/or it's windy, that the Santa Cruz is a little noisy at highway speeds, particularly toward the front of the driver's window. It's not a ton or anything, but a little noisier with wind noise sometimes than my last two cars (Toyota 4Runner, Porsche Macan) in some cases. In general, though, I would regard the Santa Cruz as really quiet.
Anyway, interesting data points, hope that helps for perspective!