I bought the Vline VL2 directly from Grom. Here's a link.
Lexus LX 470 2003 non-Nakamichi stereo only Navi GROM VLine VL2 Connected Car Android Infotainment System for CarPlay, Android Auto, Navigation, Google and Waze Maps, Music streaming apps, Bluetooth, Mirroring, for factory stereos of
gromaudio.com
The install was easy. Just watch a Youtube video about removing the factory head unit/screen, unplug the wiring harnesses, plug the VL2 into the head unit, plug the factor harnesses into the VL2 harnesses, and run the wiring behind the air vents and into the glove box where the VL2 will sit. I'm not the handiest or very tech savvy, and it was easy and quick.
Here's the camera I used.
I had to drill one hole in the metal panel behind the license plate (there is already a hole in the same spot in the plastic panel behind the license plate) to install it. You tap into the reverse light for power, ground it under the nut that holds the rear hatch lock cylinder, and run the wire under the trim from the cargo area to the glove box. As I mentioned, there is a delay between putting the trans in reverse and getting the image on the screen. Could be the camera, or could be the VL2.