hmm performance as in handling or power wise? power wise if you are sticking to your stock engine and not intending to turbocharge it, there's nothing much you can squeeze out of the engine so don't bother wasting time instead i rather you enhance your car's handling by adding strut bars/anti roll bars etc, getting a set of good tires on decent size rims for your car(probably upsize if haven't to 13"? i don't own a kancil, the sifus here can advice more), install coilovers(at the expense of your ride's comfort).
For performance on power, its usually already very hard for a 1.6L NA engine to extract power(unless yours is a mivec/vtec/etc those with another set of hi-lift cams), so either you add in a turbo charger or do a swop for the turbocharge version ie: daihatsu mira L2 engine? Kancil is a very light car so probably even a tiny increase in hp like 10hp can be felt/seem. Anyway just my 2 cents, hope it helps