Droth

Has its own GPS antenna, which you'll need to install. Haven't actually installed mine yet (unit is running on my workbench) but plan on putting it in factory location

Check out this thread on club lexus US http://www.clublexus.com/forums/is-second-generation/695451-flyaudio-china-unit-install-w-picture.html Try a company called bonroad on alibaba, should cost about US$ 520 shipped

Yes the 7" version fits air vents 06-09, the 8" version 09+ air vents. 8" still fits pre 09 just bit of a gap but you can modify a 09+ air vent to fit a pre 09

On the Roadrover versions it's just running Windows CE with software running on SD card so it's easy to change GPS software