*UPDATE*
I brought it in for the dash snap/rattle/pop noise. I had been aware of a TSB for ALL Lexus vehicles where there are plastic retainer pins that help the robots position the windshield at the factory. Once the windshield is installed, they are not needed and possibly create a rattle noise; the TSB says to cut them out. I spoke to the tech about the noise and he said removing these clips had solved the problem on other vehicles, so he would try it on mine. That was 5 days ago, and I have not heard one rattle since then, so I would say the clips were the problem. :) :) :)