Hello all. I am finishing up my build and was considering getting an MSD 6AL ignition box. I was seeing if it was worth paying extra for the rev limiter or just getting the MSD 6A box without the rev limiter. I have a built 408W that I assume will be 500HP + with a built C4 automatic. Do I need the rev limiter with an Automatic? Im using a Mallory 4755401 unilite and a petronix flame thrower coil. Last question is if i get the MSD box do i still need my ballast resistor? Thank for the advice in advance.