6g72 (150hp) would sit bolt on on your intercooler engine mounts. If your current engine is 2500 cc TD then you would not even need to change the gearbox. you may need to change the housing though (need to check). This engine is Mitsu base engine and is rugged. The price that i checked last month from isloo and Pesh was 170k including engine, gearbox, wiring ecu etc.
6g74 SOHC (205 hp)(called DOHC here) these are for about 160k and are much more powerful then 6g72. If your current engine is 2800 TD then this should sit bolt on. The gearbox of 2800 would easily couple with it less the housing...
i also saw a 6g72 DOHC (approx 188hp) at Pindi few weeks back and the guy was asking 145k for the entire package but it looked more like a car variant though the ustad jee was saying it would fit perfectly well in the 2500 cc engine bay.
my suggestion would be to go for the first 2 options only. Avoid GDI as the electronics are complex and these locals wouldnt know much about the troubleshooting part.
You should speak to Aristrocat as he has more indepth knowledge directly from the market. i am sharing what my few friends have told me while swapping engines.