SOLVED! Well at least drastically improved. I have the OT roof rack and I had removed it to reduce wind noise. It has just been sitting in my barn taking up space, so I decided to try it on the GX again. Reinstalled and drove it on the highway today, but same annoying noise over 52mph. When I reinstalled it my wife commented how much cooler the GX looks with it on, but conceded the wind noise was pretty annoying. I was going to take it back off today, but I was looking at it and I noticed that it has a rubber sort of trim strip along the underside of the front edge. I pulled down on the corner and it is just adhered on the roof rack with a sticky backside. I decided to peel it off and just see if it made any difference. IT DID! I drove it again on the highway and now I really can't hear it under 68mph and even up into the upper 70s it was only moderately noisy. My son was with me and he said he didn't really think much about it now and that it was so much less annoying than it was with that strip. I actually think it looks a little sleeker too, but ultimately it is so much nicer to drive that I'm going to leave it on for now and see how it goes. If you have a rubber strip along the leading edge of your OT rack it might be worth giving it a try to remove it and let us know if you get the same improvement.