I actually put it in before the Subaru Challenge, so I've been running with it for about 2 weeks to not only notice any changes as I go about my daily routine (I usually seem to notice something different when I'm not paying attention to it
![Rolling Eyes :roll:](./images/smilies/icon_rolleyes.gif)
First off, the filter actually does give you some sound. That was noticed immediately. There's more sound under throttle, especially above 3500rpm, but it makes the most extra sound if you let off around 3500rpm. It resonates through the car loud enough that the loose trim piece by my windshield defogger on my dash will vibrate when this happens. And I still have my snorkus in too! No, it's not as loud as my cone filter was, but we've hashed over the issues with cone filters enough on this board.
I'm guessing it took a few days for the computer to compensate for the extra air coming through; I think I noticed a tiny bit more power right after putting it in. But after the Challenge, and driving it for the next week, I felt confident saying the filter added an extra 5-6hp. It really does make a noticeable difference, not just "Well, it feels a little bit faster..."
![Laughing :lol:](./images/smilies/icon_lol.gif)
Yes, I have run a K&N panel filter before, and I don't remember it making this much of a difference. Granted, that was a long time ago, back when I was more dumb than I am now, and my car wasn't running as good as it is now. But I can say for sure that the K&N didn't make an obvious difference like the STi one does.
Gas mileage is also pretty much unaffected. I still average roughly 25mpg combined (remember, I still don't have working A/C).
Now I'm not so dumb to think that my car is going to blow any STi's away because of an air filter. That said, it might not be worth the $82.95 it costs list!
![Shocked :shock:](./images/smilies/icon_eek.gif)
![Laughing :lol:](./images/smilies/icon_lol.gif)
Anyway, part number is ST165464S000, and it fits directly in place of any car that uses the air filter 16546AA020.