My dual tour corbin is full leather. I watched them make it in the factory in Hollister.
it is on a standard/classic, but there are no air flow intake loss that is noticeable.
The ducts are missing, but there must be enough odd openings in the rear sides and around the frame that it works.
The comfort is just right for me and some people hate the Corbins.
If you are racing/maxing out the HP, then might pull the side covers.
But the BASE R3 has more than enough POOP for me. Still full of respect and awe for the carpenter guys.
I can only imagine the beast "uptuned".