Hi, does anyone know what the CIS control unit does? If this is a computer control unit that determines speed, fuel/air mixture, throttle control etc, would it be posible to upgrade my cars engine and performance via this method? I mean using a CIS from a later model, better performance model? This unit is listed in a parts mag. but gives no discription as to what it does or is for. My baby is a 1985 190E 2.3 8V. Thank you.