I have a Liveu LB100 (or something like that) and love it. I routed mine the same way as above. Through the headliner, down the A-pillar trim, and then plugged it into the socket below the glove box.
Lifehack: If you get one like the above mentioned that uses a micro SD card, it can be difficult to get in and out of the slot. I put a piece of tape on the end that sticks out about 1/2" past the end of the SD card and folded it over on itself so I can easily click it out and pull the tape rather than trying to dig the Micro SD out with my fingernails.
One word of caution: If you do get one that uses sticky tape to mount instead of a suction cup, test fit it before you mount it. That rear view mirror and all of its sensors take up a lot of real estate.
2011 335is: gone
2013 335i M Sport Estoril Blue
2011 G37 Coupe for the wifey