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