K&N filter in stock aribox?

Any proven gains in performance or mpg? I don't want an entire intake, just trying to see if a Hi-Flow filter would help at all.
Jim

I didn't notice any gains in either of my cars with the K&N drop in filter.  Definitely a better filter than stock though.

even if you don't gain any hp, the k&n will outlast the car and save a lot of money

A new paper filter is almost as much as a K&N and the K&N will last longer than I'll probably keep the car. I use to think a K&N was the way to go, I would buy one as soon as I got a new ride. Now I'm not so sure, that's why I asked if there were any gains. In the Dodge Truck forums, a K&N filter in the stock airbox has shown a 5 hp and 5 tq loss over the stock paper filter with the Hemi engine. Dyno proven by a member with a very good rep on the forum. Other members, including myself, showed a loss in MPG with a K&N. The MPG went back up when the stock paper filter was installed. The Hemi engine doesn't have a MAF though, it uses another system. Some members claim the extra air from a K&N can't be seen by the computer because there isn't a MAF measuring the air. On my Silverado which had a MAF, the K&N was a worth while mod. I also did a search on the net one time and found an old thread about some guy who dynoed a K&N in his BMW (forget which model) and it also showed a losss over the stock paper filter. I guess I'll research it some more and just have to see for myself when I get one.
Jim

Go Green if you do go the reusable route. K&N is a gauze type cotton vs. Greens woven cotton. Green uses two layers of woven cotton to catch more. I have two 4x's with the Green filter in them and there is a noticeable HP gain, but I haven't seen an MPG gain or loss. I have yet to go Green in my 3 so I have no info there.