[Alex 3]

Search this forum for mr12volt if you want bluetooth handsfree and streaming. Does not address your stated requirements but keeps the HU completely stock.

Me, I have a Garmin 7 inch GPS for nav - it comes with a wireless reversing camera. I will not state the model as the technology in this Garmin is **** and I would have junked it but for the reversing camera feature.

Whatever aftermarket system you consider pay attention to the LCD screen. Plain LCD or IPS screen technology will wash out in sunlight. QLED "may" be the better technology although there has been only one member post supporting this - albeit from Florida were the sun is a tad evident.

As we all know MB charged a fortune for updates on the Nav system and I am told in newer cars they charge a fortune to do it off the net.
When I got my last SLK320 I installed a similar system which I moved over to the SLK55.
It is a Garmin DriveSmart 60 LM which is a 6 in screen mated to their backup camera complete with the usual line references
Lifetime Maps (LM) is a bonus and I use a windshield mount which puts the screen right beside the instrument cowl on the right side where it is just on the edge of my peripheral vision. I don't have to look down to see the nav screen.
The camera is wireless except of course for a power source in the trunk and the connection for the camera itself to the transmitter.