I'm sorry if this topic has been beaten to death, but I just wanted to testify on something I had given up on. For my 2008 Spec B. My navigation Map was from 2004 or something and I had been desperately searching for an update.
I procured the Toyota_Lexus Map revision 13.1 (Toy_Lex_NAV_NA_13.1_Gen4_U28) and burned it to a Dual Layer DVD and tried plugging it into the Nav DVD slot. Didn't work.
Then after reading this: http://forums.nasioc.com/forums/show....php?t=2318458
I decided to give "hot-swapping" a try. It wasn't REALLY a hotswap, but after I loaded the map, I removed it and swapped it out for the new disc. Cycled through the Ignition a few times and so far so good.
the only downfall is that you lose the voice guidance, but honestly, I don't miss her too much.
Great to know that this works on the stock Legacy GT nav and I'll be keeping an eye out for even more updates!