So many questions, so little time. ( have to go for a ride )
Pressurizing the air box insures that more air/fuel mixture will get pushed into a naturally aspirated cylinder providing for more power.
Is it worth it? yeah if someone else does all the homework.
Carburated models have to have the float bowls pressurized to match the increase in air box pressure and FI systems have to have a pressure sensor to squirt more fuel and keep the balance.