Originally Posted by faceglide

The Fast Intentions Intake tubes are indeed 2.5".

They have run them past 650, and within safe limits. From what I have heard, they can take up to 750hp(theoretically) on their particular kit, no doubt 700 is within sight. I daily drive north of 610 on 12.6psi. On a 2.5" intake tube.

Your mileage may vary, maybe it is based on the kit setup, but they have found the stock maf easily capable of 650 without a reason for concern!