Two of the most detracting items on a car are the use of wirenuts or those cheap crimp connectors you get in the $1 bin at you local auto parts big box store. Both are butt ugly and prone to failure sooner or later. A cheap alternative is buy various diameters of copper tubing at a hobby shop. They can be cut longer and crimped on both ends where you insert a wire, or cut shorter and used as a collar where you overlap wires. They solder very easily. Soldered joints may be a bad idea as vibration can cause the soldered wire to break (not approved for most marine uses) but shrink tube provides enough support around the splice to keep it from vibrating. Small, cheap, easy, effective.