My car with these mods get about 22-25 mpg, but throttle response and low end torque you can feel a difference. Vehicle also runs better with 91 octane fuel.

I don't know for sure how much horsepower is added, but it feels like these mods help the engine perform much better.

The next mod I would suggest is converting a 1.6l Honda exhaust manifold to fit. I'm trying to find a cheap shop who will cut the Aveo flange pattern, chop the Honda tubes and reweld the exhaust manifold flange onto the Honda part. Might cost about $350 at my Local shop.