I would expect the dealer to repair the problem because it probably
indicates an issue that will eventually cause a mechanical failure of
some kind. Further, 80 mph is the average speed of any rush hour
traffic in the Nashville, TN area. Additionally, I travel, and some
states allow speeds up to 80 mph in any case. Finally, this is a
quality control issue. This vehicle is rated to go up to 160 mph, the
fact that it has problems at 80 mph shouldn't be discounted because of
the speed limit in any one particular location. As a side note, the
humming noise is also present at much lower speeds, it's just not near
as loud or annoying.