Have you called crutchfield on this? Many don't like crutchfield, but they do have a lot of resources for updating your vehicle. They can tell you exactly what you need, of course from them, but then find the products you want wherever you want.
You might try a search on
http://www.the12volt.com and then click on the forums.
That is a site for installers and what not and I'm sure that same question has been asked there or you can join the forums and ask yourself.
I know it doesn't answer the question but hopefully it will help some.