Before i even bought my IS200 I knew i wanted to install a 2 din touch screen interface with all the bells and whistles, including rear view camera, navigation, USB, bluetooth..... however ive come to learn thats its not as simple as i thought, especially because I have the factory nav. I learnt that you have to bypass the stock amp which is easy enough, but doing so would probably make the sound quality dreadful Tried to research but still confused on what complications the stock nav can cause for fitting aftermarket headunits, but know it causes problems.
So discovered these GROM units, and now they come with bluetooth and android capability which sounds too good to be true! but its not, its amazing, I can control all my music from my factory headunit from my android device, as well as answer calls via bluetooth with its in-built mic. 109 pounds on ebay.
As for the rear view camera, opting for ones of those rear view mirrors which doubles as a screen. You can buy them as a kit with parking sensors, camera and rear view mirror...