I forgot to mention the service manager said it takes between 3 to 5 months for the car to "learn" a drivers habits. So for you to notice any change, either you or your wife will have to be the sole driver.
For Ha Ha's when I was at college today I asked 3 decent size adults to go for a ride with me. And she lagged like crazy as I expected it would. 4 adults is a lot of weight for a little 4 banger to handle.
Maybe you need a turbo Veloster? Or something with a V6? Or bigger 4cyl?