I have a 12 month old update disk for sale, just sold my 2003 RX and put the original back hence the spare, the part number is PZ485-X01EU-07 (update disk 01CY), the version detail on the disk is 86271 24126, you need to be sure that this disk will work in your unit as not all disks work in all models / year, the best way to establish what disk is needed for your car is to go to the following site http://www.lexus-mapupdates.eu/ and enter the details of your current disk and it will tell what is the upgrade, if it comes back as any of the part numbers listed above then it will work.
I only want £50 inc postage for the disk but you will see on the update site this disk will cost you about £120.
PM me if you are interested.
Thanks