Wind deflector clips on using two spring-metal clips, that attach with two black bolts through holes in the deflector.

When I say whap-whap, I'm not describing wind noise at all, rather a middle-ear back pressure from the draft effect from having the opening on top at speed. Seems to cause negative pressure, drawing air out of the VX and into the opening. I used to get the same effect from my 4Runner when only the side front windows were opened. By cracking the back window in the 4Runner, the back pressure was relieved. My girlfriend's new Highlander has the same issue so I don't believe it is uncommon.

If those types of pressure changes don't bother you, then you can forego the external (add-on) deflector. It could be the very high humidity in Atlanta that makes it more noticable.

-- Best, John