CBme

Yup, the isolators will help and are really the only other option to not have to bypass if you can't fix the core issue which is usually a grounding problem. Unfortunately, fixing the core problem doesn't seem possible with this specific model and an aftermarket radio as no one appears to have been successful in doing so. Problem with isolators they don't fully mask the issue with this specific factory amp (might with some receivers, but haven't with others) and *might* negatively affect audio quality (some with this car have reported it reduced the low end for some reason).

oceanlvr

I am going to chime in....and yes...I recognize that I may be raising the dead here.
But as I recently changed out my stereo system, there might be a person out there that can still use this.

I am sure that with the length of this thread, everybody knows there is more than one way to introduce noise.
A Grounding loop isolator may be one way. But this will only work if the alternator is introducing noise.
Otherwise, it is going to be limited or totally ineffective.

What I did was use RG6 coax for my preamp wires. One of the main reasons that I used this is that it is shielded.
Even so, I found that I had some of the interference that people here are reporting.
Since I knew the pre-amp wires were shielded, I moved on to the new speaker wire in the trunk.
I then ran a second ground cable to the car body....and made certain that I had a very good connection.
Lastly, I wrapped all the speaker wires in the trunk in a couple of wraps of aluminum foil....and although I am not certain that it matters, I did it shiny side out. I then covered the foil in a wrap of electrical tape.
I would not do more than a couple of wraps of foil....and a single covering of electrical tape is fine.
Yes, you can buy aluminum or copper covering for wire...but this was 2 or so ft of something out of the kitchen....vs something that cost money.
These 2 things essentially ensured adequate grounding and also shielded my speaker wire. The end result was all trace of the interference is now gone. There is no need to worry about the wire in the doors. Only wrap what you ran. If the OEM wire had an issue, it would have started with the OEM system.