I'm also having a problem with water leaking from my driver's side tweeter cover.
My local garage has resealed the mirror using silicone from the outside underneath and around the black triangular trim but this hasn't fixed it, although I believe Lexus have tried this approach in the past from the service history.
I'm struggling to understand how blocked sunroof drainage holes could cause water to enter the speaker area, can anybody explain? - otherwise that points to the mastic in the door trim being the culprit, as per the tutorial on the site.
I don't fancy trying this myself, has anybody got their indy to do this repair for them with success?