Well, it's all based upon the laws of physics, not PR material that you read about all the time! Here's the science in a short to the point formula....

1st you need to calculate the CFM the engine with the blower is actually sucking/taking in...... next, you need to calculate what th current filter is capable of flowing......

The formula which is used by every air filter manufacturerin the world to determine the CFM for flat panel filters is...

Flat Panel CM= Length x Width x 6

So let's look at a stock 2013 Mustang V8 and assume 6,800 max rpm & 90% volumetric efficiency (note that 90% VE is race carspec and likely higher than reality) can only suck in a maximum of 535 CFM, and the OEM flat panel filter (12.375” x 9.675”) will flow 718 cfm, so the engine is sucking in everything it already can.

Standard atmospheric pressure is 14.7 psi.......so let's say that your blower is set for 7 psi......that's about an increase of 49% CFM into the engine....... so if we assume this is on the same 2013 mustang, we would do the following math....

535 CFM multiply by .49= 262 cfm

535 + 262= 797 cfm

Max flow on the oem panel filter is 718 cfm

797 cfm - 718 cfm= 79 cfm

meaning at 100% throttle and at 100% of the peak RPM power available, the engine at that point is absent of 79 cfm (ie about 9%).

However, at 500 rpm lower, I bet if you ran the calcs you would find that the engine is getting all the air if needs...... meaning, if you're racing, yes, you need the CFM, however, if your running in all other rpm ranges, the engine is getting plenty of air........ if you shift just a hair sooner, I doubt there would be any impact in street type performance that one could see........ So once you figure really what where you are at in terms of actual CFM needs, then you can decide if it's worth the $ for an aftermarket CAI.