No not a bov, a bypass valve which is what ALL car manufactures who sell factory supercharged car use. It doesn't matter where the charger is located a proper bypass valve is needed for the car to run perfectly. People with l67 who put in ATA intercooler have issue because they disconnect their bypass valves. FYI sc14 from factory have a bypass valve which is controlled by ecu and work with the clutch to properly run the charger.
You can buy them from CAPA $250 and very easy to install.
What it will do is allow air to bypass the charger when running lightload/throttle effectively allowing the charger to freewheel as you put it. When more throttle is applied the butterfly slowly closes allowing boost to come on at a steady until usually 80% when its fully closed and full boost can be acheived. Benefits included better economy on cruise and light load situtions. cooler intake as charger is not pushing or pulling against a closed TB (depending on location of TB) longer life from charger as it works less therefor less wear. It will make tuning a ****load easier trust me.
Basically you can drive around all without seeing boost, atleast until you put your foot down. Car manufactures aren't dumb these are put on supercharged cars for a reason.