Do i need an MSD Ignition box for my setup?

You need one, especially with the s/c.

Edit: I forgot to say why you needed it. It will lessen the chance of fouled plugs, a more gentle rev limiter, more voltage spark for better combustion and mpg due to the ignitions being capacitive rather than inductive (the characteristics of caps copmpared to inductors are tremendously different in the way they charge and store the charge. Inductors take longer to reach full charge than caps do - plus caps will keep a charge when power is disconnected, inductors loose the charge when power is disconnected because they store power in an electromagnetic field; all of this makes for better starts as well ), plus igntion boxes will allow you to add rpm accessories.

Yeah you need one. Espically since you are running a blower. The supercharger will increase the cylinder pressure therefore you need the added spark of the MSD to light the fire. 42lb injectors are a little big for your combo though.