No you really don't want to service cars with the K&N filter and I'll tell you why. I've seen plenty of people use that nut to put it ON the car, so tight it almost (or has) deformed the filter can.
Course if you put it on yourself, great! But chances are if you put it on and you're not a gorilla you won't need the nut!
Course if you put it on yourself, great! But chances are if you put it on and you're not a gorilla you won't need the nut!