After market stereo
 

I have a 2012 GLK without Navigation. What will I lose on the speedometer display if I replace the factory stereo. I assume the screen for the stereo will be blank. Any other features be lost without the factory stereo? Thnaks!

Contact crutchfield. Sometimes they can retain some factory functions.

Why are you thinking of doing this? I wouldn’t consider replacing the factory stereo head , it’s part of the total electronics system . For starters you loose your phone. Many components are integrated through the head unit , interior lights, stereo, phone, mbrace, and no aftermarket has this , these connections are optical. Ebay has used mb upgrades cheap. But if it’s better sound you want then look into Audison , I have the Bit 8.9 and optical interface.

You should be looking at something like this. you replace the display, with an Android head unit, but retain all of the factory interface display and capabilities.
https://4x4shop.ca/product/mercedes-glk-class-android-navigation-gps-wifi-bluetooth-2/

https://cimg4.ibsrv.net/gimg/www.mbw...8a4171f3de.jpg
And that's what it looks like after it's done

That looks great. Thanks for the info! I'll look into that.