Hi mate, the only way it will come out is by removing the surrounding fascia, there are screws round by the steering and stuff, not done it but a few people will be able to tell you where the screws are. Once its off you can then see the screws for taking out the stereo, its not too bad and believe me its well worth taking out!
As for the rear speakers, the ICE dealer that did mine said they were the biggest pain in the arse, they had to remove the back seats to remove the panels, a total nightmare!
Might be a lot less hassle to take it to an ICE dealer who would be able to do it much quicker.
_________________________
<<<< look i have a badge