1zz-fe - The one refers to it being the 1st generation of the ZZ series engines, fe is Toyota speak for economy tune. 2zz-ge - The 2 refers to it being the 2nd generation of the ZZ series engines, ge is Toyota speak for performance tune. FE = Economy GE = Performance GZE = Performance Supercharged GTE = Performance Turbo Charged. ZZE121, ZZE122, ZZE123 denote what model it is, ZZE122 is the hatch in 1zz-fe engine form, ZZE123 is the hatch in 2zz-fe form.