Hi Guys,
I am an LX470 owner and trust me I am knowledgeable about some things on these vehicles.
The overwhelming likelihood is that you have wind noise from a poor windshield installation. Those of you noticing it starting after an install are correct.
Face it, there are not that many lx/land cruisers on the road and many windshield installers do not know what they are doing.
The noise can come from different areas, but let me give you the most likely cause especially after w/s install (by the way if you bought used you could have noise from a prior install).
The LX has moldings on both sides of your windshield near the doors that run up and down. The source of the noise is most likely these moldings. If removed during an install (can be done without removing, but is tricky) they have to be reinstalled with the correct little rivets and done perfectly or you will have noise and potentially a lot of it! Gaps can get created between the rivets and the molding inside the trough of the molding. Air gets in there and makes a lot of noise. Removing the moldings kindof wallows out the holes...or they use the wrong rivets or whatever. These can sometimes be gooed up with silicone to stop the noise or replaced with the proper rivets.
The top rubber molding on the windshield which runs left to right can be a big source of noise as well. Sometimes the front edge rubber of your sunroof can be a source as well. Door rubbers can get out of alignment as well.
All that being said, start with those windshield moldings especially if you have a w/s replacement.
This is NOT a noisy vehicle no way. People like windshield installers who don't know lexus will drive a car and think there is nothing wrong with it, but a lexus owner knows there is a problem!
You may never get them to fix it, but explain what I said and it should help them. One other option....there is probably a guy in your market who fixes wind and water leaks on cars (they are mobile) and cheap...say $100. Call some dealers and some big auto body shops and ask who they use for wind and water leak checks. Someone will recommend a guy....if they are good they can nail this down and fix your problem. Advise if more questions!