Personal choice of course ... I don't use it especially with headers. The metal tube is for the ignition wire going to the solenoid and all the other wires that will junction there. It was designed to protect these wires from the heat of the exhaust manifold. If I can't find pics I'll do some drafts on paper and send.
The only thing I ever have going to the starter is the main cable and the wire to the starter from the ignition switch that also has a quick disconnect built in. All the others go on a junction box on the fire wall or a fender.
The wire that goes from starter junction to the alternator is the "sense" wire and you will get in considerable argument if needed or not... I don't use for show or street car. I hook that to the alternator terminal on the alternator itself. Gives nice clean minimalist look of wires under hood.
By using quick disconnect on the wire coming from ignition switch, means you can drop starter without having to unhook it from that stupid little 9/32 nut. Great for side of the road or parking lot maintenance. Unhook the starter cable at the battery, unhook cable from starter, drop the starter and pull quick disconnect.
Especially on a warm car with headers... Much better when working around hot or warm pipes. Skin don't like anything above 114*F.... Ouch.
When the starter is wrapped with a blanket, wire and cable can be under the blanket and cable with other pig tail is routed toward front of block and secured along pan rail. This keep cable and wire from possibility of contacting any hot exhaust, no melted insulation, no direct shorts that can burn car down.
