If your're talking about a K&N or something similiar, financially you won't be much, if any better. They need to be re-oiled over time with a kit that costs about $20 a pop, and it will take a LONG time to make up the initial investment. I bought one because the paper ones always got the crap beat out of them when I jammed them in because they didn't fit well and were flimsy. Also they didn't seem to seal all that well, likely causing a little air to get through unfiltered. The K&N fits great. Whether or not they add hp seems to be argued over and over, with neither side having any real proof. Don't buy it for performance gain, or to save $.
Submitted for the approval of the Midnight Society