[aerohead]

The information which exists in the public domain suggests that if the Swift is like the Chevy Spark (Cd 0.326) that if you fully tricked out the car,aerodynamically,that you could see in the range of 49.4 mph HWY if your actual highway mpg turned out to be the EPA rated 38 mpg as your starting point.
You'd do better than this in the city if it weren't for the cold-starts,cold restarts, yields,stops,traffic lights and congestion.
A hybrid would recover some of the lost energy as you know,at roughly twice the selling price of the Swift.