Same as the 3. I bought one and installed it a month or so ago. Sounds better...no idea on gas mileage or power as I don't drive much.
just the drop in/panel filter.
There's no way you can actually notice a difference in power or sound from a drop-in filter.
Well, you might gain 1hp due to a freer flowing mesh, hardly significant.
Most of the people who buy them from me do it to save money...you only have to buy it once.