2004 CTS (sold), 2014 ATS
Another drawback: they let in too much dirt. Oil analysis tests show that users of K&N filters have the silicon content of their next oil change go through the roof, indicating too much dirt is getting past. Add in the fact that you're unlikely to notice any significant gains, I would definitely pass on a K&N.RobertCTS said:Not sure on fitment. 3 drawbacks IMO. Draws engine heat, loud and whistles. I suggest spending a bit more and get a Volant.