04 Ford Explorer Aux Adapter

Folks,

Well, I've been searching for topics to help me for a few hours. and I've found next to nothing.  Let me start by saying my car stereo knowledge is very limited.

I have a 2004 Ford Explorer with the "Audiophile" (their word, not mine) factory system with the 6CD in-dash player.  I do not have the rear audio controls or DVD Entertainment system and I do have a SAT button that is not hooked up to anything.  I am looking to add an adapter that will allow me to connect my XM Skyfi2 as well as my iPod to my head unit.  I'm tired of crappy FM Modulators. 

I talked with some of the car audio installers (best buy, tweeter, meyer emco) and they either quoted me at numbers above $200 or had no idea what I was looking for.  So I'm attempting to at least see if I can buy the parts on line cheaper...and possibly install it with the help of some friends.  My problem is I'm not very well versed on car audio, so I can't quite determine which adapter to buy b/c I don't know what kind of pin connection my stereo has.

These are the two options...

1) The PIE FRDN-AUX/S for 20 pin connections http://www.discountcarstereo.com/detail.aspx?ID=828

2) The PIE FRD03-AUX/S for "Phase-II 16 and 24 pin connectors" http://www.discountcarstereo.com/detail.aspx?ID=820

I did run across this wiring diagram ( https://www.the12volt.com/installbay/forum_posts.asp?tid=51199&KW=ween) for a 2004 Ford Expedition and it's leading me to believe I should go with #2, but I'm just not 100% certain.

Any help would be much appreciated.  As well as any thoughts on the PIE products in general.