u can use charger 2.0A, 2.5A or so on...
it doesn't matter much.
bcoz N5 have a standard spec for charging current.
If let say charging current spec is about 1.2A, then even u use 2.5A charger, it still draw 1.2A for charging only.
For my understanding, charging time wont get faster.
But if u use 1.0A charger, then off course charging time will be slower.

There is a charging circuit within your charger and battery.
it is your charging circuit which supply the current to your battery.
And the charging circuit is design to privide optimum current for battery charging.
Event the charging circuit get more current from charger, it still maintain the optimum current to battery for battery charging.
And talk about battery life span, it is hard to judge, because usually battery only have a min spec for n cycles charging.
the more frequent you charge, the shorter the life span it will be.

Just my personal pov...

HIGH5 bro, i'm in d same condition as u.

Perai area

chill... bro
hopefully it arrive here b4 cny

looks interesting....