I finally bit the bullet and I am wiring all my accessories (bluetooth radio, usb charger tach, etc.) with a power distribution block. I chose a Painless Wiring with 7 circuits. 3 are full time and the other 4 are keyed power. I wanted to mount it without drilling holes. I used one existing screw on the metal plate where the fresh air vent is, I did drill one small hole with the self tapping screws provided. All the wires are labeled, pretty easy. I have a 50A fuse on the BAT block that feeds the car. I used a blade also from the kit behind a fuse for the keyed (accessory) power for the relay that works the 4 accessory circuits. All 7 circuits come with 20A fuses, I'll adjust those down accordingly. My tach prob draws an amp if that.