All of the above posts were right. Personally, I'm ditching all of the stock set up, and going with teh following:
MSD 6AL box
MSD Blaster2 Coil
MSD Mechanical advance distributor.
The box will allow rev limiting, as well as provide a better spark/multiple spark. Watch when ordering the coils, as some are made to work with the stock ignition set up, while others only with the boxes. If you are using a stock/near stock engine set up, then I think the gains from the box wouldnt be that great. BUT, I feel that if you pair the box up with a coil that is designed to be compatible, along with a strong distributor and a good set of plug wires..then you will feel gains. In race/performance motors, definitly invest in a quality ignition.