Thanks for all the responses. I just looked and I think there is a CD changer under the passenger seat. There is definitely two speakers (subs?) attached to the rearmost barn door. No HK labeling, and just a casette tape on the head unit with a "CD" button.

I'll look for the amp under the driver's seat tomorrow. I don't even know how to get at the CD changer cartridge under the passenger seat! Lots to lean on this truck...

 

There's a little door/hatch on the front panel under the passeneger seat that flips down so you can get at the CD magazine. Regarding the speakers, just look at the front door. If you see a speaker grille down by your feet in the front of the lower bin, a small speaker grille towards the top of the door panel by the window and a little speaker grill on the trim that runs from the dashboard up to the ceiling then you have the HK high-line system. Otherwise, you don't.

 

That simplifies EVERYTHING in regards to what I have... I have all those! So I have the HK high-line system! Now I can start working on making it better, so it sounds better. Now the only problem is this (I don't own a Cassette, I have very limited CD's, BUT, I have about 20GB's worth of downloaded music on my computer hard drive and 12GB's of that on my Phone!) Oh and I also have a portable Sirius/XM Receiver that I want to hook-up, and the way the system is now, IT SUCKS! for both these options!

Thank you very much 04duxlr for the help and information! Anyone have any solution ideas for my selected 2 forms of musical entertainment?

 

There's this: Rover LandRover 99-05 USB Android iPod Bluetooth AUX car kit or this: Land rover RAnge rover discovery iPod iPhone interface adapter with aux audio input rasio mp3 or this: ROVER LANDROVER 99-05 AUX-IN Android iPod Bluetooth Adapter
Of course at these prices, an aftermarket head unit with aux inputs is probably cheaper.

You can also go this route for less dough but it isn't nearly as slick an integration:
I've used this in other vehicles and was very happy with the sound.

 

See I like that Scosche option... I could do something really cool with the switch/input device, so that would be pretty good. But is it direct connection to the radio? Or FM trans? This one ROVER LANDROVER 99-05 AUX-IN Android iPod Bluetooth Adapter(GROM-AUX-RVR) is direct connection and seems like it would be the best sound option. Plus, I am going to need something that will work both with an iPhone 5 an Samsung Note!

 

It is an FM modulator but it's connected through the antenna wire so there is no hiss or loss in transmission like the wireless ones. There are two fm frequencies to choose from way down on the left end of the spectrum (or dial for us older folks that know what that means), just set the switch on the unit to the frequency that has no fm station on it. You tune in to the frequency you picked, switch on the modulator and enjoy. It doesn't provide any way to control the iPod, but even the controls through the aftermarket head units are a little awkward when driving. It's probably easier to be able to just pick up the device and control it directly. You can make or find a switch to go between the iPod and the Sirius/XM so you can leave everything plugged in.

 

Yeah and it is only $18 instead of $140, $200 by the time I get all the adapters that I would be needing for it. Thanks for all your info, great help!

 

you can unpulg the CD and buy a cable to pulg your MP3 player into your head unit and not even remove it, a simple cable you can get on ebay.

 

Well I can't find said cable on ebay... Maybe I don't know the terminology to get it to come up on the search! Thanks though, I will keep trying!

 

I've just cut into the CD cable under the passenger seat and added a 1/8th plug to the passenger seat control panel. I like hard wiring over FM. Means no CD player and the sound shuts off for a few seconds when the discs shuffle, but the sound is great. And it cost $3.