Iv got a hks race suction on my 9 and it makes an awesome noise, but then iv had a group a k&n on my old focus rs and that helped it breath better and gave a puka note .... Don't think this helps u much but thought I'd chuck it in anyway ; ) lol
It was on the car when I bought it. But I have read they aren't the best at filtering so might be worth having a dig around on some of the forums to find the best choice for induction.
I would go with the k and n. I had a hks one on my old car and i would haveto clean the air flow meter ever 5000 miles as i let to much crap through. Plus hks say you have to change the filter after 20000 (i think). Have k and n now nothing goes though and it sound cool to!