I wouldn't use K&N, I looked at both K&N and Mobil1 and decided not to use them. Mercedez was closed due to Sandy so I opted to wait a few days to get one from them and I'm glad I did, quality wise it's 10 times better. I'll get them online next time but I just got my SRT so I wanted to change out the oil as soon as possible.. glad I did because the filter that was in there... well I don't even know if I'd call it a filter lol.