I hesitate to write this because I only recently realised that my understanding of what MRC has been doing was wrong. However if you check out this thread you'll see that what MRC do is to change the crank pulley for a bigger one rather than the supercharger pulley for a smaller one. So their stage 3 is based on using an even bigger crank pulley which needs slight block modification in order to fit, and then additional cooling. Based on what Doug has written I don't think it matters much if you have a stage 2 crank pulley and a reduced supercharger pulley or just the stage 3 pulley since the challenge then becomes how to keep the engine cool.
I believe a lot of the Audizine guys are going upgraded crank pulley because the OEM one could delaminate causing damage.
The bigger lighter aftermarket crank pulleys are single piece so do away with that risk, but yes, I agree, extra cooling is a must if going this route.
The way of tuning most times, with the extra heat and power required to drive the charger the actual gains are not what you might expect. Also the supercharger is always turning at a higher speed at any time so wear and longevity come into it as well. It's like driving your car 1 gear higher all the time.