all of the oil contamination stuff is just hype, the only way the oil from the filters would get in your engines oil is if you have bad compresion and blow by problems, if your compresion is bad the least of your worries should be your air filter. the thing to worry about is the mass air flow sensor being contaminated, you can clean the maf sensor but eventually it will fail, and they arent cheap. the hp increase you get from these filters is minimal, to the point you will never notice it. so in other words take the 60 bucks the filters would cost and save it for a cold air intake, you will notice huge gains of hp and torque as well as gas milage increases when you stay off of the go pedal. most of these kits will come with a k&N filter, if your worried about contamination of your maf sensor or other contamination you can always order an aem dryflow filter, which does not use oil and offers excellent flow and filtration, is reusable, you cant crush it, and has a lifetime warranty. i run the aem filter on my xf and love it i also run an aem filter on my truck with a brute force intake system on it, as well as the truck i had before that. i never had any issues with failed maf sensors with these vehicles and i trust aem. but thats just my opinion.