I'm siding with those guys who have mentioned things that add to comfort. Like the seat covers. A center arm rest if you don't have one. Inexpensive stuff like that. There was one member that is doing / has done like a strip down to the bare bones adding insulation project. While that is way far above and beyond what I would do, I think that is probably the only way to really dampen out the noise.
However, the noise is not that bad in my opinion. Originally I was thinking to improve the sound system a bit. Yet, if you do and have to turn it up over the road noise, that would tend to wear on a person (noise on top of noise as someone else said, is a good point).
My biggest suggestion is that when you wear out your tires, research to find the quietest tires that fit the car, and go with those. I recently put really quiet tires on my wife's Toyota Matrix. Oh man, what a difference ... especially at highway speeds. HUGE improvement.
View my fuel log 2020 Mirage ES 1.2 manual: 42.5 mpg (US) ... 18.1 km/L ... 5.5 L/100 km ... 51.0 mpg (Imp)