Ipod controller that allows you to control from nav screen is a $500 option but my salesman threw it in for free along with window tinting (08 GS 350).
I just took a test drive of the 08 GS 350. The salesman said that the 08 model has an AUX port so you can connect your iPod or similar device. However, you cannot control your iPod from the car's controls, with or without navigation. He did not know of any $500 option that would allow for control from the navigation screen. Also, there is no hard drive option for the GS cars; the LS cars now come with a hard drive.