You addressed Brian, but I can reply as to the success I've had with K&N filters in other makes of cars as well as my 1987 300E.
The least expensive performance increase that can be had.
Don't tell anyone you are using a K&N Filter for there are those who have done their own testing and find the K&N Filter to be inferior in filtering the intake air.
Discount the manufacturers who OEM K&N Filters.
Happy Trails Beep Beep from Houston!!!
Donald, El Cheapo