Want to install a stock stereo

My car has a Pioneer CD player in it that I really don't care for. It doesn't sound that great for one and its asking for someone to break in and steal it in my 'hood'. My Ranger stocker stereo sounds TONS better, and the Mach460 stereo in my Mom's 02 Mustang of course sounds better still. So in light of these events, I want to return to a stock radio in the car.

My understanding though is that there were 3 different head units available for these cars. A 'base' one, the 'premium sound system' and the Mach460.

How can I tell which one I need?

I DO know it's not the Mach 460 unit. No mirror speakers and no package tray assembly.

I don't know how to tell if it came with the premium sound, or the base stereo though. Is there an easy way to decipher which one? Can i check the harness plug or something? they used an adapter on the Pioneer unit (at least they didn't cut it right?). From what I remember the stock harness plug is pretty wide, flat and gray. I also don't appear to have ever had the remote CD player. I have the little cubby.

Lil help?

It actually has some aftermarket speakers in it and it still sounds like poo. Well, at least the rear shelf has aftermarket ones. I didn't pay attention when I last had the door panels off.

So the head units would be the same if it had the base stereo or the "premium sound" setup? From what I've read around, the premium sound system had an amp hidden under the dash somewhere.

The Mach system would be a nice stock upgrade, but man... the trunk space that it eats up is nuts.

The sound just seems to lack clarity, bass and definition really. It sounds... "cheap". hard to describe sound in words lol.

The car is not a Mach 460 car though. I don't have the little triangle speakers nor do I have the fiberglass box under the rear deck. Ill have to pull the head unit and see if I have both plugs under there. I only remember a gray, flat rectangular plug under there the last time i looked.

Oh, how do i pull out an aftermarket radio? I know the little tools are available with the Ford stocker, but are there tabs or something I need to pull before taking out the aftermarket unit? I'm totally not an audiophile, so every car I own has just had stock radios in them.