I have not got the zune subsciption cause I like to put them on CDs for my car. I might if it sounds good through AUX though ill order a cable I guess and try it outIt's very tolerable - not as good as CD or a high bitrate file via USB but sounds good enough IMO. If you're playing music downloaded from Zune subscription you probably won't notice much degradation due to the bit rate of the recordings (192kbps) you're starting with.
It's worlds better than the alternatives (i.e. FM modulator).
From looking at that kit, it seems your net gain is the ability to charge the Zune. A creative person could find a way to do the same w/a cigarette lighter or direct connection. For sound, it looks like it's still 3.5mm straight through or a 3.5mm to RCA which is nothing special. You can do everything this kit will do now a lot cheaper.http://soundgate.com/index.php?request=product.details&categoryid=309&productid=629&usereferrer=1&snd_SID=74cf092bea3a6f15391882405
just found this. definately will be purchasing one very soon