Is there anyway to switch between the XM channels that I have put into memory presets using the hardware "track buttons?"  It seems they just move up and down one channel above or below the current channel.  On the Z1 there were two sets of buttons, track and playlist that one set would move one channel at a time and the other would move between the memory presets. The manual says you can use the "track" buttons to change between HD radio presets but is silent on this on XM...

Not sure it's possible. It works using steering wheel controls though.

Unfortunatly 2005 Mustangs have no steering wheel controls.

There is a steering wheel wireless option. Search this forum for details.

Yeah I have the steering wheel remote along with the PAC interface since my car doesn't have steering wheel controls. Works pretty good