I just bought the latest upgrade (11.1) that came out Nov 2011 for $169. I have an 06 Prius and this is the first upgrade I've done. I haven't had a lot of problems with finding locations so waited until the price came down. The dealer showed me a chart that indicated how much the system upgraded for each year after 06. I also looked at the coverage area for the Northwest and then checked the difference in coverage with the new disc...it just about doubled the area covered. I had a lot of problems figuring out how to put the blasted dvd in so for others who have a Gen II: The navigation disc unit is found beneath the driver's seat. Access it by moving the seat all the way forward so you can access the front from the rear passenger floorboard. Take the plastic protection cover off (two plastic clips). Now there's a button on the left side of the unit that says "push". You have to push in and then to the right and the old disc comes our automatically. Insert the new disc and replace the housing. Now check that it works properly by checking the "map dvd" in the "Menu" portion of the navigation console...you can see "covered area" there as well.
Toyota updates the Nav DVD's every year around October. The number of the revision is the year. So the latest will be the 11.1.
Quick question will this new 11.1 Navigation DVD gets rid of having to manually hit the "I Agree" button ? thank you