Siena: Those numbers refer to Engine Capacity in Litres.

Size isn't everything when choosing a car. If you're doing most of your driving in busy, built-up areas with slow traffic, a smaller engine will do just fine. If mostly long highway trips, then a bigger-engined car will be a more relaxed drive.

Somorin#1:
OP, your choice depends on the intended use.

IMHO, there is no reason why a well engineered 1.7 liters powered car cannot perform adequately in Nigeria.

Now, if you typically carry a full load of passengers and/or luggage then the efficiency of the larger engine may be beneficial.

It's all up to how you want to use the car.