I actually pulled the rear (non-folding) seat and seat back out to run my wires properly. It actually works awesome, especially having the internet on the headunit itself! I have TMobile and I already have a cell and tablet on my plan with unlimited data, so I added another unlimited data tablet plan and popped the SIM card in. That's the easiest way to stream and you can still select songs from your phone.I ended up getting and installing the Avin Android 10 w/ 8.8 Touchscreen & SIM card capability. You could also get a cheap adapter (I used to have and it worked really well) and plug into your aux port if you have one.

In my personal opinion it is too much work to upgrade to CIC for what you actually get out of it. Combox was never an E60 option so I believe people have to do some work flashing the CIC with something like the E90 had or something. Upgrading to CIC will certainly look more modern and I believe since it has a hard drive lets you store music on the car (do people still do that?). I also have MASK but what I really wanted was wireless Apple CarPlay so I ended up getting an Avin unit and it's working fairly well for me (uses the iDrive controller as well).

E60 idrive upgrade