I have been over this before, so I'll be brief. The K&N panel filter that fits the 124 does not flow any more air than the stock filter (at least not on my flow bench). Although the actual materiel in the K&N is more free flowing, it's offset by its reduced filter area. In other words, the stock filter has deeper pleats and thus more area. So in terms of performance the two are essentially identical.
So what does the K&N filter offer? Simple, it's washable and reusable. Lots of people have been using them on Multiair engines and they work just fine. They don't filter quite as well as some other options (my opinion) but they don't let anything through that's large enough to cause any measurable wear. Generally speaking objects greater than 10 microns in diameter cause most engine wear and down to that level the K&N filters pretty darn well.
Greg
Note: This post is 124 specific. In many cases the K&N panel filters have deeper pleats and do outperform stock paper filters. I don't know why they dropped the ball with the 124 filter.
So what does the K&N filter offer? Simple, it's washable and reusable. Lots of people have been using them on Multiair engines and they work just fine. They don't filter quite as well as some other options (my opinion) but they don't let anything through that's large enough to cause any measurable wear. Generally speaking objects greater than 10 microns in diameter cause most engine wear and down to that level the K&N filters pretty darn well.
Greg
Note: This post is 124 specific. In many cases the K&N panel filters have deeper pleats and do outperform stock paper filters. I don't know why they dropped the ball with the 124 filter.