Originally Posted by GewoW
Less than pre-2010, but I still believe there is SOME performance gain.
There might be a bit of a performance gain or none. What you'd gain for sure is a lot more dirt into your engine. The engine is just going to breathe what it needs, and an AA '08/'09 filter (stock but without the charcoal) probably provides all the air a stock engine needs, but without the extra dirt. No free lunch: more airflow (your engine might not need) means more dirt, and any gains (if any) are at the very top of the rpm band. At least where I live (desert), no way I'd risk engine damage over the long run for a few HP, but that's just me. And if you don't believe the many independent tests of racing filters (cotton gauze) vs stock, do your own with a shopvac, by blowing dirt thru the filters with a damp white shop paper towel at the other end. Whoever thinks a racing filter is going to filter anywhere close to a paper one is watching too much TV. Or don't care about his motor