So I installed my Omnifi DMP1 yesterday and well it's the BOMB! I f'en love it!
But in the procees I came to a halt when I realised my stupid Pioneer had a funky-ass setup for auxiliary connections. Pionners don't use RCA's for inputs, they have their own "IP-BUS" plug which I though would leave me stranded with having to use an FM modulator

. So I went to Best Buy and talked to the mobile-audio dude there, not thinking they'd be much help. But what the hell.
Anyway after talking with the installers out back, one of them suggested I use the XM->Pioneer interface module as it converts the RCA output from an XM radio into the Pioneer IP-BUS input; and sure as sh!t - it works! Cost me $50 for the module but it's worth it. I got back a lot of mp3's I had made from CD's that were stolen from my car a year ago, plus I have a ton more.
Now to start downloading like a fiend to fill that 20gig HD!