To be honest, you wont get a whole lot out of the air filter and tube. Maybe, just maybe 2-4 rwhp. They will advertise for a lot more than that though. Take my advice and get an air filter that is reusable and does not require to be oiled. The oil will get on your MAF (mass air flow sensor) and gum up the filiment, causing you to detonate like a mofo.
This is what happened to my 00 Mustang GT with a K&N filter. (before I got rid of it, the GT that is)
I had to regularly clean the MAF with electronics cleaner to keep it from giving me trouble.
edit : i cant spel.