I believe... I read that the 17's are going to be Michelin Pilot HX MXM4s.. This is a very pricey tire..
its because when the cars all makes and models are shiped to the dealers they are on fake tires made for transporting...and when the dealers get them they put real tires on it...
I've seen about 5 Gen 3's in the UK now at dealers - and all the 17" equipped cars had Michelin Primacy HP tyres on.
Just bought our 2010 Prius V last night with 17" wheels and it came with Michelin Pilots, 215/45. This is in Richmond,VA