I am thinking of purchasing am airaid cai for my 2012 mustang gt. I am going to use the mvt insert so I don't have to use a tune. I have heard of a few instances where a slight lean condition occurred even with the insert. Has anyone had this issue or is it safe to use without a tune? Muscle mustangs and fast fords installed this kit with the mvt and no tune on a bone stock 2011 gt and they said it caused a air/fuel ratio that was a tad leaner than they like. But they never said it was dangerous to the engine. Any info would be greatly appreciated.