exactly what i've been looking for! please keep us posted!
GETTING THE PIECES TOGETHER:
I got the listed parts also and they are exactly what you'll need to get a 2 DIN radio centered correctly in a 03 ES 300 CD radio replacement - I bought a Pioneer AVIC F90BT ( 5.8 inch screen) radio for an aftermarket replacement unit and it has the gap on each side . The standard screw mounting holes on the new receiver align to Lexus brackets perfectly. The top to bottom fit was great -just the side gaps need help.
I haven't removed the factory radio or installed the AVIC F90BT yet so I don't know if it will fit depth wise into the dash cavity but it should. Also I read that the AVIC F700BT is a better color match but you lose some features.
I'm shopping for a filler plate material also - the smooth shiny black plastic on the AVIC F90BT front is challenging - I'm sure there's material available to do a nice job - TAP plastics maybe, BUT I haven't looked around much though.