I use the audigy 2 nx in my SUV.... works great.... I use the RadioShack 3 foot mini-plug to rca
plug cables and run those directly into my amp. Sounds crystal clear.
My music and any other non-AC3 media plays thru all the speakers because of Creatives
CMSS 3D which upmixes or puts out a stereo signal to all channel pairs.
I use the stereo signal output.. works really well.. even the center channel being used
sounds good when just playing an mp3...
Good luck.... its worth it... the first time you hear 5.1 surround sound DVD
in your vehicle you just can't stop grinning