Another update on the Michelin CrossClimate+ --
As I mentioned before, definitely noisier than the Nexens were on smooth pavement, but a different noise spectrum. Un-scientifically, it sounds like a higher frequency white noise.
There is also some mileage impact -- I would guesstimate about a 0.2-0.3 mi/kWh drop compared to similar circumstances (temperature, speed, driving style, etc). I usually get 3.8/3.9 mi/kWh on my way to work, and around 4.1-4.2 mi/kWh back (difference being mostly due to temperature changes). These numbers were pretty consistent for my commute the past couple of weeks on the Nexens. Now I get closer to 3.5/3.6 mi/kWh into work and around 3.8/3.9 mi/kWh back.
Most of my driving is highway at around 75 mph. Mornings have been in the low to mid 40s and afternoon in the mid 60s.
I had read somewhere in this forum that someone put some sound deadening mats in the trunk of the Kona (on all the exposed metal). When I looked on Amazon, I found this:
https://www.amazon.com/gp/product/B012B5EMGO for $32. I put them in last night, never having done anything like that before. It was easy and took me maybe a half hour, start to finish. So now all the exposed metal in the trunk is lined with the Noico mats, and the bins sit on top of that. No problem fitting the bins or cargo floor back in after applying the mats. You can probably get away with a mat kit 1/2 the size of this since I have about 1/2 left after covering the trunk.
This morning on my drive to work, the car seemed like a cone of silence (relatively). Absolutely amazed with the difference! Most of the high frequency white noise from the tires is gone! Who'd have thunk?!?