You can ditch the ecu but I think you need to keep your ballast resistor, not sure though. The installation diagram for the MSD shows the red wire going to your old coil + wire. The coil + wire gets its power directly from the ballast. The ballast is there to step down voltage to the coil, because full voltage is too much and will burn it out. I know some aftermarket coils don't need ballast resistors at all, but some do, so you probably still have to run the correct ballast resistor for your specific coil. Or does the MSD unit somehow 'know' how much voltage your stock coil gets? I can see if you run an aftermarket msd coil, but for a stocker?

Anyone else, am I wrong or am I right? I've had a msd 6al sitting in a box in my garage for a while that I never did get around to using yet...