depends what you wanna do.. n/a or boost? n/a probably d16y8 for higher compression.. although when you go to do internal mods it wont' make too much difference for you will be getting higher compression pistson for either.. so i'd say stick with your d16z6 and build that.. they both have ~ same hp and tq... if any difference at all.. i'd stay with OBD-I over OBD-II anyway