a drop in K&N filter alone is not going to add much more the 1hp to your car. now if you remove the resonator and pipe in some cool air to the airbox that setup is worthwhile.

a drop in K&N filter is really only worth it for the cost savings not for hp.

i would get this brand instead www.greenfilterusa.com instead of a K&N since they are known let in a lot of dirt.