The car already has a pulse width modulated electronic boost frequency valve to control boost. If you add a separate boost controller, then you run the risk of damaging the engine, since the stock MAP sensor only goes to ~2 BAR, and the stock tables really max this out already.
Basically if you increase boost, the ECU looses the ability to add the correct amount of fuel. Not worth it, unless you are changing to a totally custom stand alone ECU, or you want to restrict boost to LOWER than the stock limits.