A clean neat instillation doesn't take much time. A little careful planning will yield a neat professional installation. Wires you don't use may be cut close to the fuse panel or neatly coiled and tie rapped for future use. (Remember extra ignition and accessory wires can be used to power remote fuse blocks with the use of relays) Unused wires should be capped (end wrapped to prevent shorts) and secured to the wire bundle. Wires are best routed on the inside of the vehicle (especially going to the rear of the vehicle). For a battery mounted in the trunk: Route the cable inside if possible to protect the cable be extra careful of the main battery cable (Battery to starter) to avoid any sharp edges or contact by seats or moving items. Use a sealed (vented to the out side) battery box or a sealed battery (optima or odyssey) Secure the main battery cable (tie wraps Adel clamps etc) so it stays were you want it Use Grommets or bulk head (pass through studs) Junctions. (part# 110-20 or 110-30). Even if the bulk head is wood or fiberglass