Depends on what you want. The Popcharger is cheaper and looks a bit flashier, the Stillen looks more stock, and is more expensive, but is higher quality and utilizes the stock "Power Duct". Both probably net about the same gains, but neither will really make your car any faster by itself. The pLenum is where the power is and either intake will work well in conjunction with it. Both intakes are basically the same design, so should sound about the same. Search around; there are nemerous threads discussing the intakes with pics.