I have a AVH-P8400BH, which has App Radio features. I have a non-jailbroken iPhone 4. The App Radio features do work, but they are persnickety and prone to freezing up and otherwise doing things I don't want. It feels like it's not quite there in terms of development.
I think we used a Metra install kit to fit the head unit in the dash.
I do love the sound quality, the easy control of the iPod, and the display.
By the way, I still have my stock BRZ navi head unit, and the accompanying amp and speakers, for sale...
--Dan
Mach V