I just wanted to confirm with everyone that YOU CAN install a double din aftermarket radio/navigation unit into a 2004 Lexus ES330 using the face plate on the first page. I just completed doing it myself and it worked BEAUTIFULLY! I am really happy with the results. What you will need:
1) Lexus Double Din Face Plate (Part #: 5540533230)
--if you want, you can just use the brackets and screws that are currently holding in your standard radio as these will fit the double din as well..otherwise you will need to purchase those (listed in first post)
2) Wiring Harness: Metra TYTO-01
--this worked great with integrating into the factory amplified system you have..it does not list being compatible with Lexus but I can assure you it works in my car, as this is the part that Metra Technical support told me to use
3) Trim Piece: Metra 95-8202
--as mentioned earlier, there is about a 1/2 inch gap on each side of the aftermarket unit when placed in the Lexus Double Din Radio Faceplate....these trim pieces fill in these gaps REALLY well....they almost look factory. I also noticed about a millimeter gap between the top and bottom which I filled in with a piece of felt..(really minor gap...maybe not even noticeable)
That's all you need to fit in a aftermarket navigation unit or double din stereo into a 2004 Lexus ES330. I can say that I had it installed and have been LOVING it. I installed a Pioneer F90BT. One thing I must say is that after the install, my factory sound system sounds MUCH better for some reason with a lot stronger base, as well. I guess this could be attributed to the new unit. My unit came with integrated bluetooth and ipod so I have that in my car as well. In addition, I also added a rear view camera (Boyo VTL-420) that attached on my license plate.
It took me quite some time and a lot of phone calls to make sure all the parts would work (especially since most of them don't list Lexus compatibility), but I can tell you that the parts listed above DID work for me in my 2004 Lexus ES 330.
I will try to post some pictures to show you how it looks.