I thought I'd give it a try after I did the math.  You know, $12 per regular filter x 4 years = $48.  Fit was perfect but my 2003 Silverado runs noticeably better!  I had seem some folks comment on this in other reviews but took the 'see it to believe it' stance.  Well, I have seen and now I believe.  I'll never buy another regular air filter again.