There's a good mechanic on Jamshed road, Total Petrol Pump street, workshop is named Raja Autos and mechanic name is Ishaq.
I've done some research on engine swap for my Pajero Mini and concluded that if vehicle is with auto transmission, then change both engine and gear with their control cards. No need to change differencials. There's a bit of difference, but it will not impact top speed.
If its manual transmission, only engine can be swaped with everything intact. Manual version is 5 speed, which handles 1100cc good and maybe bit of improved top speed.
This vehicle's fuel consumption average is about 10kmpl max, it will not get better. It's a proper 4x4 mini truck built for off roads and tough terrain. Mechanics tells stories to cashing you out and keeping themselves busy.