Audio Systems: 99 explorer eddie bauer stereo, explorer eddie bauer, speaker grilles

Question
How can I tell if I have a premium or Mach stereo?  It says neither on the stereo front nor on the speaker covers.  I ask this because Crutchfield asked me what kind of stereo I have...I have no idea without pulling the panel off the inside, and I don't really want to do that until I know if I need just the speaker or the entire box with speaker, amp, fans, etc.  I'm getting answers of 8, 4 and 2 Ohm and different cone shape...etc...I just want to know what it could cost and try and source the part on ebay.

thanks.  KA

Answer
The door speaker grilles usually are labelled for Mach systems. Mach systems are more common on Mustangs. EB Explorers almost always have premium systems. That just means there is a separate amp/receiver in the rear passenger side of the cargo area. If you remove your head unit with Ford radio removal tools, you can see for sure. Check out http://www.installdr.com/QuickWiring.html
and click on Ford wiring.