MSD DIS-4 works wonders for a boosted applications. I highly recommend it for any UN-natural aspiration. Main reason is the soft touch rev limiter. Factory rev limiter is in the fuel and not the spark. In a boosted car (including nitrous), if you bump the rev limiter, the computer shuts off the fuel injectors in stages. Obviously, shutting the fuel off in a boosted application is a BAD idea. The MSD has a soft touch rev limiter built in. When you bump the rev limit it shuts off spark to the cylinders in a controlled sequence. It doesn't just shut them all off, it rotates the cylinder cancellations to limit the revs. This is much easier on the engine. The MSD is also capacitive discharge and gives you multiple sparks and much more energy. The result is more complete combustion without problems. The MSD DIS-4 sells for $400 and we've got them in stock.
When we do a blower application, we use our SCT Tuning and a MSD unit for ignition. I roll up the rev limiters in the computer, then do the control with the MSD. There is also a retard function. You can pull timing out with the MSD (but you can't advance it) based on RPM. So in our boosted applications, we'll set it to ramp timing out starting at a certain rpm. This too helps the engine stay together.