Hey Matt,
I doubt you will beat the price of a kit by building and buying all of the components to wire your car yourself but, if you decide to forge ahead. Look to this guy for your wire.
This is an excerpt out of my Astro build...
As I have been pulling together the wiring I have found some excellant suppliers with high quality products. The wiring books were a couple and here is another.
If anyone is in need of automotive wire give Nate Garland at
Welcome to Wire Barn - Your Trusted Wire and Supply Source a look. He sells a number of different types with GXL cross-linked polyethelene being one of them. This stuff is a far cry from your basic PVC covered junk.
He sells it in 25' lengths in multi-packs of six or eight colors. This is perfect for a home builder like myself as I don't need 100' spools of wire laying around. It's also a helluva lot cheaper... I just bought 1 ea. of the 18ga, 16ga and 14ga 8 color packs from him and paid about what I would have for four 100' spools of 16ga. This is more then enough wire to finish up the van and probably a couple more projects down the road. With 8 colors and three ga sizes I am pretty well set for wire for a while. He also has 12 ga and I'll be picking up a selction of that this week.
Here are some pics of the wire he sent me. It is very nice stuff. And it is made in the USA!!!
http://images60.fotki.com/v224/photo...MVC017F-vi.jpg
http://images107.fotki.com/v159/phot...MVC018F-vi.jpg