I think the one mirror thing is because it's using the rear view mirror of the normal Nascar/other MODS and there isn't a split view to use.
Plus the OWR racing tracks have modified track.ini settings for more grip to replicate the greater downforce from the wings.
These ones I think by the looks of things.
track_asphalt_grip = 1.69
track_concrete_grip = 1.67
ai_grip_modifier = 1.400
But remember to change it back or swap files (or copy & rename folders) if you go back to the other Mods.