I find it odd that is their recommendation as well. I worked in auto service industry for nine years and we performed five wheel rotations on plenty of vehicles, never keeping three tires on one side all the time.
My theory on rotations is to always do it the same every time. I would follow...
Like others stated, pretty simple to remove and improves the look of the 4Runner a lot. Doubt the MPG difference will even be noticed at the pump, everyone drives with a heavy foot these days anyway.
The hex-head screws are 10 mm and once removed you'll have two plastic tabs in the middle...
My hood flutters on the Sport Premium. It's not a lot but it is there.
My 18' Tacoma Sport flutters significantly more and has not been an issue in the 93k miles its been driven.
The Tacoma gets pretty crazy at highway speeds when passing a semi in high wind conditions.