Ive noticed the same sort of thing.
I also have a rattle from the engine bay at high revs that echoes through the car.. Although i did have to leave the Typhoon bracket off and i think its this which is vibrating...
Not sure....
I havent noticed a massive improvement either if im honest, the BHP claims of K&N and Kinetix should have given approx 20-25 bhp..
I dont think ive got half that..
Anyone else noticed a big/dissapointing difference??