Did you find the exact rims? I was also looking for stock rims for my 2009 Lexus GS 350 but I ended up ordering a set of American Racing rims from 4wheelonline. When I bought my second hand GS 350 it didn't go with its original wheels.
I would like to upgrade the tires on my 2009 Lexus GS 350. So far I have checked out Toyo Tires' Proxes 4 Plus. Does anyone have experience with it? Any other recommendations?