HFI may looks stock (if you want that I guess) but the short ram just makes it really come to life. Especially after taking the audio module out that makes the fake engine noise, it starts to really sound like a Honda should. Makes the BPV a lot louder, throttle feels a little more responsive and I could tell boost lag dropped a little too. Reoiled the filter twice since I got it and I'm really happy with it, kudos to PRL, it's a really efficient design and looks/sounds fantastic too!