Hi all. Looking to replace the plugs in My 2014 Kia Rio. I was looking at the plugs on Rock Auto. All the iridium plugs (Denso, NGK, Champion, Autolite, etc.) have different spark plug gaps. Anywhere from .032 to .044. I was thinking of going with the autolites as there is an active rebate. They say .044 gap. Why aren't they all the same?