Mine came with a satnav, but if it didn't, I would have hardwired my Tomtom. I actually prefer it to the Ford satnav, though the inbuilt one is neater. I also have a dashcam hardwired. That's the only modifications I have made.
Having had the B Max 2 1/2 years now, I have enjoyed every minute of it and will really miss it when the time comes to replace it. Not sure if the new Fiesta Active will really fit the bill when the time comes as it's not so high and I found myself bumping my head getting in and out of it.
B Max Titanium X 1.0 125 bhp in Magnetic with built in SatNav and rear sensors.