You wont find a G13B in lahore & you wont find a G16A in lahore too
You are left with G13A, G13BB and G16B
G16B would make the biggest dent in your pocket and you will be having alot of troubles relating to transmission and suspension. It is a heavy engine for the cultus body.
You are then left with G13BB and G13A. As I have heard market is flooded with G13A which are carbed engines which will make your life easier. PLus they are 16 vavle engine rated around 70-80 hp. My guess is that they will cost least.
In the end a 1300cc engine would be best suited for you preferably G13A. Yes G13B is a monster but you wont find it anywhere.
And yes let me tell you that which ever engine you choose, you will be facing problems every now and then. My friend has a 1300cc engine swapped in his car. His cultus is very famous here in lahore. Simple say mods hai aur har dosray din us ki gari mein koi masla hota hai. Maheenay mein 1/2 haftay woh workshop mein rehti hai