Ford Focus Change Air Intake?

What kind of K&N Air Intake should I get for my Ford Focus 2009 1.8l Trend AT 5dr?

Any aftermarket intake below the $1000 range will be a step backward. Modern stock intakes are designed for the engine; cheap aftermarket intakes are relics of the 1970s when stock intakes were crude affairs.

One time a customer wanted their K+N air filter cleaned by me. I declined much to the chagrin of the SW. I said I'm not touching that. After cleaning you add some sort of recharge which then gets on the MAF and codes. What a cluster. Takes 30 seconds to change a boring air filter. You do the math.

Don't bother. K&N are not all they're cracked up to be. You won't get any appreciable power gains. Stay with the stock filter, it works fine for the life of the car.