It does feel a bit more responsive, looks great and you can hear the turbo whine a little more also the dump valve is a little louder. Personaly I would think any aftermarket filter is going to be better for performance over stock whether it be an element or open cone, filtration is the only factor really. The Foam types like HKS are supposed to be the worst followed by the stainless steel mesh type like Blitz or powertec. Any cotton type filter should provide excellent filtration qualities (K&N, Green, Apexi) the only difference is that K&N use a 'wet' filter (use oil to help catch particals) and the Apexi is a 'dry' type cotton filter. The negitive od using a wet filter is that the oil used 'can' over time clog sensors which can lead to the ECU picking up wrong signals and messing up the air to fuel ratio etc. their are no disadvantages to a dry filter apart from they may not offer the same filtration properties as the standard paper filter but from what i researched a while ago my mind was put at rest when I found that the apexi filter does filter the air really well and offers a really good performance gain. I find it very good. I'll dry and find a link to the web page but cant promise anything.