Hello Zetec, welcome to the sight. I'll try to hurry this so i can give you the first reply. Others here like to jump on newcomers for one reason or another. Here's the help I gave to another newcomer the other day:
I suggest going to the main page of the forum http://www.mp3car.com/vbulletin/ and reading everything in the FAQ and Newbie section.
From those two sections you will find plenty of unfamiliar terms to search. This will give you a basic idea of what is needed. You can then do a more detailed search on each item you may want to consider for your set up.
After you decide the main components you want in your car, search some more to find out how each wire, connection, and configuration is done.
I've been reading and searching for months, I now understand how to hook up each component that I have selected for my set up. I have a shopping list in Excel with prices and links to those products, and I constantly search for better deals. I'm spending a lot of time considering each and every wire, adapter, hardware and software I will have to buy before I go into the spending stage. Confucius say, measure twice, cut once.
There are too many variables to give you one answer, so you have to do a lot of searching to see what works for you and your set up. That should be plenty to get you started.