Green Filter 7159 グリーン 高性能エアフィルター

Really good filter more air more turbo sound fits perfectly in stock place

Good whistle in 3rd, but no flutter. I do recommend it though.

I drive a 2013 Ford Focus ST and it's Everything I hoped for. Had a stock filter, switched to this high performance filter and it is great. Personally, I noticed a slight increase in throttle response, and high end power. If you're looking for a power adder, this isn't the ideal product, but it does help your car breathe ALOT better. The best part about this filter is the INDUCTION NOISE AND OH MAN is it sweet. Turbo sounds come through alot clearer and louder and you get more spool noise when boost kicks in. I run this without the factory intake lid, because this filter comes with a 'O' clamp to bite onto the intake piping. With the lid, there is still noise but to maximise noise I run it without. Expectations were met and I do reccomend this filter.

What a difference 60$ makes. I've put aftermarket air filters on my vehicles before (K&N), but they've never made such a night and day difference in sound as this one does. Construction is solid, no rips or tears, and installation is super easy, even if you have little/no experience with mods. I installed it over my lunch break in roughly 5 minutes. Once installed, you'll actually hear and feel the turbo spool, and you'll hear the stock bypass valve recirculating air when you let off the throttle, both of which always put a smile on my face. The car feels like it breaths better and the turbo spools faster, but as someone who speculates just how much an aftermarket air filter contributes to additional HP and TQ (looking at you K&N with your ridiculous claims of 30hp gains), I unfortunately don't have dyno numbers to prove the difference. TLDR: Love cool turbo whoosh noises? Buy it. You won't regret it.

I have Focus ST 2017 its fit it and turbo sound is very nice , I recommend anyone have Focus ST to buy it