For forced induction, where you have a tune that changes AFR and/or timing when the meth is flowing and increasing octane like race gas would, it is nice to have the tune operate only when the meth is operating. This is almost more important with the supercharger than with the turbo. You can set up an Aquamist failsafe to drop boost on an electronic boost controller regulating boost on a turbo. However, you cannot set up an Aquamist failsafe to change ths supercharger pulley for lower boost if the meth goes out. The Procede is nicely integrated.
On the other hand, the stock ECU will take some advantage of race gas, so simply adding an Aquamist on a naturally aspirated car should provide some gains. Ideally, you would take full advantage of whatever extra octane you have, and that may be beyond the range of the stock ECU when meth is flowing -- which would make the integrated meth and tune the best way to go. I am also not sure how immediately the stock ECU adapts to the higher octane of meth or race gas.