I just finished two simple additions.
First, Tour-pak spoiler with light. Surprised to find out it's powered by the Accessory plug which is connected to a brake light component.
Second is an air horn.
Never connect to existing horn wires. Use of a relay has doubled the volume.

 

Which air horn?

 

Metalarts. Looks like puffed up oem horn. Has a wolo inside. Metalarts service stinks but the horn artwork is their best thing. Closest looking to oem.

 

Very cool. I like the retro style long horn.