yea the bonus to a say up like an AVR + SAFC is that you can tune to our conditions and your specific mods, and have different settings for colder weather race gas etc without having to reflash, its basically 2 separate units that added together basically make a $600 utec, plus they have some nifty other little gizmos that you just cant do with the stock ECU because it wasn't designed for it. that being said if your going to go all out Id do a reflash or utec instead of buying those and then eventually having to buy a utec or do a reflash