OK, First thing :
I DON'T KNOW ANYTHING ABOUT CAR AUDIO

Now, I do know some things about home theater and audio. I buy DVD-A because I appreciate the difference.

So here's my question :

With my last car and with my RX8 I'm struck by the complete lack of 5.1 or greater sound for car audio?

I do NOT want a dvd video player : that's completely not what I'm looking for and not the answer I want.

I want to take a DTS audio CD and play it and get 5.1 out of it.

I want to take my DVD-A or SACD discs and get true multi-channel audio out of it.

Can you do such a thing? I've never found it, but then again I haven't looked in about a year. I know it would likely require changing the amp and doing anything to the 8's stereo is a bitch, but I'm just curious about the technology availability rather than the direct application to my current car.