My 2018 Spark has 68,000 miles on it and the only unexpected problem is I had to replace the battery at 65,000 miles.
As one could probably guess, I do alot of highway driving, and do get 33MPG doing 80MPH. For one tank of gas I did not go over 65 mph (That was difficult!) and did post 38mph. I have no trouble getting up to speed quickly and there is ample power to pass travelling at those speeds. Just steady, strong pressure on the gas pedal and the CVT gives me suprisingly strong acceleration.
Changed the tires at 60,000. Purchased some that were better on the freeway