I ran a Digital 6 in my old car with no issues. Two step and rev limiter are built in as well as a start retard. A Digital 7 has the ability to adjust the timing curve for individual cylinders as well as a different one for I believe up to 6 gear changes. Some models have slew rate adjustments, retards the timing if the RPM's climb too quick. Not legal in some classes though. Inputs for NOS retard also adjustable. You don't want to be holding the coil wire on this one!!!! :shock: