K&N Air Filter; Better than stock???

[RPX5]

Just replaced my factory air filter with a K&N, and I wonder if anyone else has done such a swap.

I've noticed the sound and acceleration seems a bit more "raw," almost as if my car isn't liking the swap.

I definitely installed it correctly, and it fits well within the factory air box, but I read that pre-oiled filters (such as the K&N) cam sometimes damage parts within the engine.

I did notice, however, that my average gas mileage (03 4.4) has jumped from 15 mpg, to 17.5 mpg (everyday city/highway driving).

This is a good sign I'm sure, but back to the sound and acceleration feel, it isn't so "tight" anymore.

Any insight??

Thanks!