I would agree with Doorracer. Painless sell quality wire, also I wired a car for a friend of mine, Doug Bracey in California sold him some wire that was embossed with Water Pump, Fan, Fuel etc it was pretty good stuff.
I use 14 awg TEW wire. it is rated at 220 F. multistrand and flexible. The insulation is heavier and it is rated to 600VAC. This is a type of wire that is used in electrical control cabinets for industry. The down fall is that it only comes on rolls 250 feet plus. It does come in a wide variety of colors. I also have had heat shrink tags made up that I put on the wire in various spots to help identify the circuit.
For wire rating
Voltage
Temperature rating
Multi strand..TEW 14 awg would be 41 strands