Audio Systems: OEM Replacement Radio, old radios, mazda b4000

Question
Hello.  I currently have a 2006 Mazda B4000 truck (the sister truck to the Ford Ranger).  It came with an AM/FM/CD Radio with the 16/20pin interface, its a slide in style radio.  I am wanting to upgrade my stereo to an OEM AM/FM/CD Radio with the AUX and SAT buttons, slide in style.  Also, I want to get the HD interface so that I can have HD and IPOD hooked up and running along with the SAT option.  Because I want to do this, I am needing a 16/24pin interface radio.  My understanding is on my current radio the 16pin is for the power and operation of my radio and the 20pin is for the changer option.  So would a 16/24pin interface radio work and do they make them that are slide in version?

Answer
new radios are 24 pin for power and speakers
old radios the 16 pins are the power and speakers

the most important part is the way the radio mounds in your vehicle is by side clips
new radios are screws you can still find the radio from a mustang or expeditions that will work  2001 to early 2004
the  
a good place to start will be ebay look at the front and back of radios also most of the new radios need factory amplifiers or e-mail oemautosound.com look for andy  we knows a lot about ford vehicles