It's the good ol' 1ZZ (1.8) & 3ZZ (1.6), but it's tuned to accept E20 in Thailand. I wished the Southeast Asian markets got the the 2ZR & 3ZR though. I'm not sure what they stand for, but G is like the luxury spec model. Toyotas sold in the south east Asian/ Taiwanese markets followed the same way grades are named in JDM land since 2000/ 2001. :) Other grade names used by Toyota Thailand, for it's range of carss; Q (Ultra Luxury-spec, above V.) V (Luxury-spec, above G.) S (Sports/ Base, depending on the model.) G (Luxury/ Base, depending on the model.) E (Economy (Mid-range/ Base) spec) J (Basic grade. used on the Vios, Yaris, Avanza & Corolla Altis 1.6)