thanks for the tip - is there a difference between the 51515 and the 51515R filter wise ? or is just a hp version like the Fram HP1 - HAVE been thinking of swithching to the Wix after all the positive comments on the Wix as opposed to the HP1 I've been using since I can remember - my combo is 440 with 2 inch Hooker super comps - HP is tight against rad hose (rubs) - thanks - Joe
