I just finished my big 3 upgrade. It wasn't as difficult as I thought it'd be. This car is a dream to work on compared to my old Buick.
Here are some pics of the wires I added. The gigantic blue ones are obvious. Those are the new 1/0 gauge grounds. The red one is my 4 gauge amp wire running to my trunk.
And this one is the new battery + to alternator + cable. The original is still there, just in case my new cable is shoddy for some reason my car won't die on me. The new one is marked with red arrows.
I was surprised just how easy it was to make it look like it was supposed to be there. The original rubber boot from the alternator was a little snug but it fit and covers it perfectly. The wire loom was freakin huge compared to the stock loom, but it doesn't look too out of place.
I'm really happy with how it all turned out, especially the cables. A big pair of vice grips, a flat head screw driver, a hammer and a piece of concrete seemed to be the perfect tools for the job. Electrical tape (to protect the connector while hammering it down) and some heat shrink really made it look nice too.
I'm not really a "noob" when it comes to stuff like this (I've been doing similar things on a much smaller scale with computers for about 10 years), but this is my first time screwing with anything under the hood of a car, other than adding my amp wire.. and if I can do it without much hassle, anyone can do it.
Do your big3 everyone!