This post outlines hardwiring of my Valentine One radar detector. The same instructions can be used to wire almost any aftermarket electronic device. If I can do it, anyone can do it. Seriously. The toughest part is probably removing the (sometimes stubborn) plastic fuse panel trim piece.
Skill Level: 3/10
This is the idea behind the wiring:

Parts:
- Add-a-circuit kit (left)
- Valentine 1 hardwire kit (right)
- Zip ties

Tools:
- Flathead screwdriver
- T20 torx screwdriver
- Credit card
Step 1: Mount V1 on windshield using suction cups. This will give you an idea how much slack to leave when routing the power cable around the upholstery.
Step 2: Open fuse panel trim piece it is held by four clips. Prying with a flathead screwdriver is the easiest way to remove the trim piece. Wrapping a paper towel around the flathead to avoid scratching the plastic piece. It should "pop" out of place if you apply the right amount of force.
Step 3: Run power cable around uphostry, a-pillar, behind trim piece, and into the fuse box area. Credit card is handy for tucking the cable behind the a-pillar piece.
Step 4: Attach ground wire from the V1 hardwire adapter to body. Pick a bolt that's attached to the metal body frame.
Step 5: Connect cable to port labeled "main unit". Use provided velcro to attach V1 hardwire adapter to fuse box. Use zip ties as necessary to keep things tidy.
Step 6: Add-a-circuit kit is the easiest way to power an aftermarket accessories - just plug into any fuse slot .
Remove a fuse that turns on/off with ignition. Replace with add-a-circuit. Place original fuse in lower slot. Add a low amp fuse (3 or 5 amps) in the top slot.

It looks like this after the add-a-circuit kit is installed:
Step 7: Last step is to connect the add-a-circuit to red cable from V1 hardwire kit using the supplied wiring harness connector. Wrap the harness around the add-a-circuit red cable, crimp, and connect to red cable from V1 hard wire kit.


Wiring after everything is connected.
Step 8: turn on V1 to make sure everything is good to go BEFORE reinstalling the fuse panel trim piece!
Step 9: Reinstall trim piece. Done.