I am new here but suprised there is no audio/video/security section. The mach systems can be confusing and I am amazed at how many shops still think that you can't add items to it with out replacing everything in the car. They use a couple of funny numbers in their speakers to make it difficult but it actually isn't hard to tweek it with a couple of minor things to make it scream. page 2 of my cardomain page shows how to install a deck in a mach460.
http://www.cardomain.com/ride/2395420/2