A blow off valve is there to equalize pressure when you are shifting, or letting off the gas. Pressure is created because of the turbo or the supercharger, and you do not want that to still be forced into the engine when you are shifting or off of the gas. When you let off the gas, the blow off valve opens and releases the pressure built up. It is usually the high pitched noise you hear on a turbo car, if they have an aftermarket one. I never heard one for a supercharger though.
If you get one for your supercharger, you want to put the blow off valve before the mass air sensor, so it can sense when there is less air coming in. If the mass air is before the blow off valve, then when you release the gas, the mass air will still think there is a lot of air going in, when the blow off valve is releasing it, causing the wrong amount of fuel to go in your engine.
I am not familiar with that model
vortech, how many psi will it be pushing? I am not sure how much people run when they start putting blow off valves on. Someone else should know though.
Hope I informed you a bit on the functionality of a BOV, but sorry I couldn't help you with your specific application.