Newby's Radio Question

Most of you are into performance here. I have done some of that myself, but my question today is about the radio.

I just purchased a new '04 Gran Prix GT1. It has the base ETR AM/FM/CD with 6 speakers. I would like to replace that radio with an aftermarket unit that plays MP3 format CD's, and also has XM or Sirius compatibility. Pioneer or Kenwood make inexpesive unit that do that, but they only drive 4 speakers. I don't want to lose 2 speakers.

My question is: Has anyone done this or similar replacement?
Is there a kit available for this conversion?

I am more interested in MP3's than satellite radio, since I have an extensive library of the kind of music that interests me.

the front 4 speakers(mid woofers & tweeters) are all driven off the same channel, so you only need a 4 channel output from the deck. your installer will wire it properly to drive all 6 speakers. I would also look at the JVC LH-300 - the lcd matches any interior and has aux, sirius and MP3 playback.

If you upgrade the deck get ready to put some money in a good set of component speaker because the stock front components suck =(

Which is the better system XM or Sirius?

sirius - less channels NO ads
XM - More channels Gay ads and shitty signal