If you want to improve fuel economy then sell this car and buy some cultus or vitz. When we talk about engine swap, there are two options:-
1- Bolt on Swaps
In this kind of swap your existing engine mounts are used and no major surgery is required in engine compartment. and most likely Your existing axles will used. Is tarha ky swaps zaida tar sahee rehty hy, ECU waghira ka masla hota hy liken jab ik bar fix kerwa lain phir koi khass problem ni hoti.
2- Non Bolt On Swap
There will be lots of cutting and welding done in your engine bay and most likely your axles will also be replaced. I never seen people satisfied with this kind of swaps. After month or two, their car needs work and if you are not into racing never do this. Also car balance get disturb and it is very difficult to control the car over the speed of 60
But ik cheez jo dono swaps my hoti hy wo yeh ky ap ik local assembled car ko modify ker rehy ho, local cars ki body already bohot weak hoti hy aur breaks b farigh hoty hy. When you increase engine power, you need to upgrade your breaking system and shocks as well to bear this much power. And on top of it your cal's resale will be zero if engine is swaped.