I'm about to pick up a CL-s with navi and was looking to upgrade the head unit / navigation system. Since the stock screen is what is used to control the heater / ac I was thinking about just keeping it, getting a video in module and replaced the Bose HU with an aftermarket unit from either Clarion, Pioneer or whatever brand offers the best video out capability.

Does anyone have an in depth knowledge of what the different brands offer? It would be sweet to have the navigation show up the on the stop screen, while having the bottom screen show something else or vice versa.

 

I recently replaced my Bose head unit with a Pioneer AVHP4400BH. You will definitely lose the voice portion of the nav as it runs through the OE radio.
The nav unit will still operate, just no voice prompts.

At first I thought it would look dumb with 2 screens, but I quickly got over it and think it all blends nicely. The Pioneers are pretty nice, it will even display netflix from my phone when changed to aux.