I am trying to find a source for the lower wire in the picture. I think it is an 2/18 copper braid shielded wire. Any clues? The only place I found something like it will only sell it in 100ft lengths.

http://www.awcwire.com/part.aspx?partname=stj-18/2

The location I need this for is the harness that runs from the passenger footwell ECU to the 2 front ignition amplifiers.

It's an extremely complex harness which looks like it has seen several attempts by the PO to fix.

Any advice you might provide is sincerely appreciated.