The big size injectors would be ok for fuel economy if not sequential and you are meaning to drive them grouped (1 - 4 & 2 - 3)? I like coil per plug for this reason: I will not having spark plug cables in the engine bay so less electrical noise and more spark energy to the plug. One last thing: The original MAP, TPS, ACT, CTS, CPS and phase sensor can be still used with the emerald ecu? To be honest now I am between theese two ECU's : Emerald and Gems and the only thing that the gems is not having is 2 different maps , all the other features completely covered.