so the xmod doesnt have a line input?
if the onboard sound is disabled in bios, it will be like it doesn't exist so your line-in wont exist. but it will at least tell you if theres a conflict so you can take it from there
i have a via epia m10000. tiny little motherboard. i originally had it under the passenger seat but not its in my trunk under the floor next to my spare tire. but it has 1 pci slot and comes with a little card you stick into the pci slot that has another pci slot on it so you can side-load a card. so it takes up room horizontally instead of vertically. i upgraded the little card so it accepts two pci cards, so i have the sb-live in 1 slot and a wireless ethernet card in the other
the sblive is ok. ive never had a very picky ear though even though im a musician.
do you hear a difference in the car with your mp3s through the xmod vs the regular onboard sound?