Anyone know where I can get the XM and Sirius receivers for the Z1, at a good price? My dealer wanted to charge me around $350 for XM.

Also, does Pioneer make a dual XM / Sirius receiver (one unit) so if I want both I don't have to stuff two components in my dash?

Any pioneer dealer should carry both. The sirius and regular xm are $99. The XM with traffic is $150-200. Try online like crutchfield or ebay if you have too