I just bought an 05 LS430 and my dealer installed the soundlinq from Vais. It is AWESOME. Much much better than the FM transmitters. If you are at all touchy about the quality of the reception, you will most likely be disappointed with FM transmitters.

The VAIS hookup sounds even better if you have the Mark Levinson system. The only downside is that you cant do all of the functions that the ipod offers. For example, you cannot pick a specific song out of your library and go straight to it. You can only select different playlists.

My personal preference is to have my entire library of music included in my "Master" playlist and I just hit the 'next' button on my steering wheel controls until I come across a song that I want to hear.