Just to let you know, we have been using a newly designed S&B Powerstack filter in our Duratec induction kits. These filters have, lets say what looks like the nose of missile, attached behind the inverted cone section. This is supposed to straighten out the flow or make it less turbulent as it passes through the filter. S&B also has tapered the interior edges of the collar to also enhance the air flow as it exits the filter. This is the theory, as noted by the literature we received. I'll see if I can get a pic.
