So I've got my M5 that I acquired from a member here on my 18", and it looks pretty spiffy.
I've got the four long panels on the back side, all the way around. However, the two six-rib panels are too long to go on the sides, or on the front bottom if I use the vert grip.
I take it I need the shorty four-rib panels here?
Also, what's the purpose of the plastic bit ahead of the side rails? I don't remember reading about that in the manual.