It's good that you're searching for a good mechanic. I cannot suggest you one since I am not in karachi but I can tell you from experience bad mechanics (even the EFI ones) will cost you 10-100k by messing up stuff.
I have a chevrolet joy and I must say it has too many sensors and is way electronic for simpleton mechanics to understand it. Just like they cannot understand many of the new 660cc cars with advance electronic system based on too many sensors. Simple EFI mechanics who work on corollas can't fix it either in most cases.
Also, it's a small space and a small engine with specific compression requirement. So if there is any head work, never get it done by those who do not know this car. If they mess up even one thing, it will do much damage.
Never ever got to someone who isn't literate enough to understand EFI engines. I have heard stories of mechanics taking out the ECU just to remove flash codes.