Just finished replacing the Magnadyne M11 navigation/stereo unit in our rig. Thought we would post some tips if anyone else was interested in upgrading.
For the Freightliner, Amazon sells a direct plug-in harness that will save some time. The stereo we bought had a harness also and the two just needed to be wired together. The wires are standard colors so as long as it was done correctly the first time, all you have to do is connect each wire to the same color wire from the other harness. We used solder seal wire connectors to make all of the connections. I hadn't used these before and they really make the job easy! Just plug in the wires and heat the connector. The bead of solder inside melts into the wires soldering them together and the casing shrinks to grab the wires so it saves a bunch of steps.
We found that two of the wires on our original unit were reversed and had to be traced. It turned out they were reversed and then reversed again in the next harness so that they could be wired directly in our harness. It was strange, but it worked out.
We went with an Atoto S8. I won't review it here, and there are many alternatives, but so far we are very happy with it. It's fast, bright, and has all the bells and whistles: GPS, steering wheel controls, a 4G modem, wifi, any map app you want, and a bunch of other stuff. It has plug ins for front facing cameras, TPMS, birds eye reverse view, you name it. We picked it because the screen floats, meaning it can be positioned higher or lower and angled toward the driver.
This is the harness we used: https://www.amazon.com/dp/B09CTLCRK6...ing=UTF8&psc=1
These are the solder seal connectors: https://www.amazon.com/dp/B07HCNTZ2Z...ing=UTF8&psc=1
This is the Atoto unit: https://www.amazon.com/dp/B085C6KLFX...ing=UTF8&psc=1