Mentioned were the cabin air filter and the intake air filter. Both provide benefits noted. The intake air filter is for the engine, which produces both power and efficiency. The cabin air filter provides comfort. Both are performance and comfort replacement requirements. Your intake system has been modified to include what is commonly know as a hot air intake (HAI). This means when you run your engine, it 'sucks' air from the engine compartment. This area is quite a hotbed (pun intended) for thin air intake higher than (versus) ambient air temperature outside the engine compartment. Some will argue that when driving down the road, this influence becomes moot. I know the lower the intake air temp, the more dense the air molecules, hence the more efficient the engine runs. We also know the program in the ECU adjusts engine parameters. The standard is a certain IAT , with a designated octane rating, at a certain altitude, results in rated power and efficiency. Although these references have a certain error span, your BEST results result in a clean air filter intake, for efficient operation in all cases.


The cabin air filter provides both comfort to the occupants AND efficiency. The most important part of this equation is the efficiency of the air conditioning system. When it is providing adequate 'clean' filtered air, the compressor runs less, and contributes to a more efficient comfort and engine efficiency. If you do not need air conditioning (heated or cooled) then the cabin air filter is the lessor of the two absolutely necessary replacement options. You be the judge, starving your engine (or not) and/or feeling comfortable? Good luck!