the difference is noticeable between the k&n and the itg.....firstly it appears that it helps to provide on my car a very flat torque curve! the car feels even smoother now....the air supply to the engine seems to be a lot better too! the sound is slightly quieter than the k&n.....
all in all brill! and for those of you that are going to the vauxhall show at santa pod tomorow come and have a look at the installation! 
