No air fiter is going to make the GX faster or get better mileage, only sound better. Also the OEM intake system is sealed and draws air through the pass side wheel well. This design is to allow the vehicle to drive through deeper water and draw cooler air from outside the engine compartment. I personally recommend the aFe Pro-Dry dropin lifetime filter. You just tap it to clean it and replace. The GX is not and will not be a performance vehicle. NO ONE has EVER been able to hack the OEM ignition codes for Toyota vehicles so don't waste your time and/or money on so called hp replacement chips.