Great question! The awesome thing about the stock ATS airbox is that it actually pulls 100% fresh air from outside of the engine bay. While we will offer an upgraded filter for even more air flow, the stock airbox is by far the best solution for most applications on the ATS. Our design works by virtually eliminating the multiple flow restrictions that are found in the OEM design between the airbox and the intake. By thoroughly studying the flow, we were able to design an intermediate pipe that transfers the cold air from outside the engine bay efficiently and seamlessly into the engine, with minimal losses. It actually does it as efficiently as a conical cold air mounted further away. I think the important thing to remember here though, is that these parts are meant to work together as a package. While we can talk about adding single components, I feel like we're not going anywhere by doing that. I say this because adding a single component isn't what we are after here. We're after true performance and actually increasing the driver's experience. True performance won't come from an individual component, not in the ATS at least, and in order to increase "performance" we need a complete system. While a single component can get you better peak numbers....peak HP doesn't measure things like "spool time" and other factors that are measured by the drivers experience when judging a "performance increase".