Could someone enlighten me about the rearmost section of fairing that, on some late-model RRs, covers the clutch and extends rearwards to the frame spars and on others is cut back (or forward) so the clutch cover is exposed. Just looking around at post-2010 bikes and some do and some (mainly Repsol) don't. Is this an optional, add-in panel or a different fairing lower half? Does it imply some other differences too?