I just acquired a 2004 performance model with no stereo. It had an aftermarket HU and still has some amp wiring. It appears to have the stock 6 speaker configuration. no factory sub, no CD changer I can find so I suppose that means it's not a Bose system but I really have no idea what I have.
I might just go back with a factory HU but need to know if it's Bose or non Bose and if there are any issues with installing a used factory unit like security codes or what ever.
If I go with an aftermarket HU can I use the stock harness (with adapter pigtails) for front speakers and pre outs for a new sub amp?

 

No factory subwoofer = no BOSE.

However it is also possible someone might have removed all the BOSE stuff, then put in a full aftermarket system but removed those goodies (amps + sub) when they sold it. This would explain why some amp wiring remains.

Either way just go with new aftermarket stuff, especially if the wiring is already there.

 

^^^ This.

The factory system is a piece of, well, you know. Easier and you get better quality and features.... Aux-In, CD, Bluetooth, etc. I have everything but Nav in the JVC HU I installed in my '03 that cost chump change.

 

You mention being uncertain if the car has OEM (Bose or Clarion) components.

One way to determine this is checking the components. Remove the front door panel and inspect the speaker.

Here is a picture of the Clarion speaker:



It has a paper cone and only handles 40 watts.

 

While I used to be a head banger and crank my stereo since way back in the days of 8-tracks with no amps honestly I don't really need much of a stereo anymore. Now I'm more interested in the sound of the engine than the sound from the speakers. Also I rarely drive more than 15 minutes at a time.
While I still have a pile of components from several vehicles I just want something to fill the hole in the dash and be louder than the engine on occasion.
So to keep it simple I think I will use an aftermarket HU (with adapter pigtails) if I can use the original wiring to the front and maybe rear speakers and maybe add an 8" sub tube and small amp and call it good.

 

^^ You can do that... And it's easy if you have the OEM Clarion system, and not so easy if you have the OEM Bose system.