6A10 is a cruiser engine, think of a Perdana going 180kmh on the highway. Because it is much heavier, it adds to the stability of the car running at high speeds. Spare parts will be hard to source.
4G91, 1.5L fuel injected engine which is perfect if you are concious about fuel consumption.
4G92 1.6L Non-MiVEC, so-so engine but the problem comes when you look for your spare parts. Reasonably hard to find at a price.
4G92 1.6L MiVEC, good engine with power to boot. Parts are readily available as it is one of the more popular engine mods.
4G93, 1.8L non-turbo variant. Stock in our Putra's and GTI's, good horsepower for an Normal-Aspirated engine with many ways to further mod it.
4G93T, 1.8L turbocharged. Also known as the GSR, this is probably the most powerful stock engine you can legally transplant into a Wira 1.5L.
As for fuel-consumption, with any engine if you drive with a lead foot, you will always have high fuel consumption. If i drive steadily on my GSR, i can easily squeeze out 420km on my full tank. If i whack it, it only gets 320km. Simple logic.
And wow, the prices have gone up so much. I only got my GSR for 6k inclusive of labour.