Just FYI, the Pro-M is really not bigger its better. Inlet size is 85mm, outlet is 75mm. If you measure stock MAF it's the same. Stock DOES narrow down inside to 70mm and has the big post in the middle both of which cause turbulence..thats the problem. The "bullet" shape of the Pro-M may also act as a velocity stack of sorts..similar to how AEM and some others shape the base of the filter..
