They streamline the air flow behind the fuel caps thats all,
I noticed a smaller V fuel stain behind the fuel caps after than before the fairings.
There has to be a fair amount of turbulent air behind the fuel caps without the fairings.
I was doing some touch up painting at the 2 rib/ fuel tank area , so I decided to put the fairings on.
I scuffed the the area real rough , used structural epoxy, super fill, UV smooth prime,EP420 epoxy primer, then aerothane. Maybe overkill ? I was using most of these things on other areas anyways.