That screen thingy is an Ultragauge, I bought it for the sole purpose of monitoring the coolant temp (15 year old BMW and all). It has already helped me once when the radiator fan quit(again) while driving around in town. It hooks up to the obd port and requires no additional power.
The little black box in front to the tacho is a Bluetooth transmitter. Aux cable goes from it to my head unit. It draws power from my phone charger. I mounted it there so since its the only place where the mic is directly in front of me and also it’s the area with the least vibrations. Quite nice to have handsfree for $20. Its this thing if anyone is wondering:
Its an Aukey Dash cam. Draws power off my phone charger as well. This and the Bluetooth thingy draw power using a Y cable from the same USB port, I’m assuming that the Bluetooth thing doesn’t draw too much current to burn out my fuse. We’ll see.