I'm not sure which ARFs you are referring to. I know Eflite has some ARFs that are labelled "25e" and even just "25" (in the case of the J-3 Cub). I admit that may be little confusing, but then Eflite only makes electric planes! They use the 25 and 32 numbers because they have outrunner motors with these designations, which indicates they are meant to replace .25 and .32 nitro power plants respectively.