SRT Hellcat engines LOVE to breathe! Our continuous testing of this engine in Chargers, Challengers and our new Hellcat Durango all have shown that the stock airbox is a major restriction. Even with the same pulley, we saw an increase of over a pound of boost in back to back testing. Boost=power and coupled with cooler, more dense air, the results were great! Click here to watch the video and see how we dyno test for proof of performance.