The mileage of Hyundai Verna Fluidic 1.4 CX is 23.5 kmpl (Highway) and 19.6 kmpl (City). The mileage of 1.6 SX is 22.32 kmpl (Highway) and 19.16 kmpl (City). So they are very close when it comes to mileage. The major difference is in the power. 1.6 SX has a more powerful engine than the 1.4 CX. So both the variants are good, if you need more power for a little less mileage go for 1.6 SX else 1.4 CX is a very good car.
While developing the platform of the Baleno, Suzuki focused on reducing weight and improving the vehicles performance by concentrating on the underside of the car. For this Suzuki created simple shapes that resist deformation. While doing this the Baleno got a smoother shape with no bends.
This, in turn, helped Suzuki create a stronger structure that could do without reinforcements. Minimising these components, Suzuki was able to reduce the weight of the car by 15% or 100kg.
The new age materials that Baleno uses helps it achieve high strength with comparatively low volume of metal. Due to the low volume of metal, it achieves better performance (power-to-weight ratio) and better fuel efficiency too due to low kerb weight.