Here is a thread in a stereo forum with a neat way to pipe your PC stereo through the DTS AMP in the Winnies.
I have a great PC and use it for my music files as well as getting it ready to use for HTPC on a new TV. I was figuring out the best way to work with both the DTS AMP or a replacement and a good Dash stereo unit I want to replace the Magadyne with. Not sure of that spelling.
Anyway, here is a useful link some of you might find helpful.
When I am parked I have full internet access and use ZUNE music on my PC, now I can run that music through the coach system.
HOW TO: Get sound from PC to Car Stereo / Amp - MP3Car.com