aem=only obd2 standalone EMS. that and like kpro. and those are fairly pricey, but theyre good, and not much more than the alternative, which would be converting the car to obd1(now its hard as shit to pass emissions) so you can run a obd1 ecu. all you would need to do that is the ecu conversion harness($100), and any obd1 ecu($50-120), plus whatever tuning software you get(last i heard, s300 goes for $425ish).


expect to spend atleast a grand on the aem unit.