I was looking at the Alpine PXA-H510 - it is a processor that accepts optical inputs. It produces the analog signal which is carried a very short distance to the amp.

This processor is best suited for dvd/video installations, and since I had no future plans for putting a screen/DVD in my car, I decided against it.

I've not ever seen or looked for an amp that will do the D/A conversion but there are tons of processors that you can get that do.

I still want the sound card though - my receiver at home accepts both coax and optical digital inputs - and I plan to build a home component sled for my empeg at some point.

EDIT: I meant to refer to my home install rather than my car in my previous post... oh well...