Hi and welcome,
I read about this issue when I was considering importing my car from the US.
Indeed, the European navigation DVD's don't work in the US models and vice versa.
However, I remember reading about a workaround once, but this requires you to modify a DVD image by combining the US DVD with the European one.
You'll need the following:
1) European Lexus navigation DVD
2) US Lexus navigation DVD
3) Blank DVD-R DL disk
4) DVD-R DL writer
5) A DVD burning program like Nero (To create an image of the DVD and burn the new image)
6) Image editting software like Isobuster or winiso.
Steps:
1) Create an image of the US navigation DVD.
2) Explore the European navigation DVD and copy these files to your harddrive:
- ALLDATA.KWI
INDEXDAT.KWI
and IDX catalogue
3) Open the image file that you created in step 1 with the image editting software.
4) Overwrite the files you copied in step 2 in the image file you opened in step 3.
5) save the file
6) burn image to disk
More info:
http://www.lexusownersclub.co.uk/forum/ ... opic=28034
If this doesn't work for you, maybe if you contact Jospeh or Shapa from that forum.