Originally Posted by shiv@vishnu
just an fyi, the power gains are likely coming from the MAF signal misreading airflow which increases the boost target. So the power is coming from higher boost pressures, not from a reduction in intake restriction. So if you already have a tune that runs more boost, you will not get an additive power bump as it will run too much boost.
The stock box/filter isn't measurably restrictive. Even with the turbo maxed out, running full bolt-on mods at 360whp. All you would be doing is sucking in hot air which is the last thing you want to do in this application.
Just my 2c,
Best way to clear this up is by doing a before and after dyno on a tuned car.