What he said.

Clarification on the efficiency part-
you won't be getting more MPG with the centrifugal over the M90. The efficiency is when you're making power. Takes a little less energy. Its also better because the air charge isn't as hot as the M90. Also the power curve a little more ideal, I think, because it builds boost with RPMs (you still get great low-end boost and torque), which helps with launches and transmission life.