It very much depends on the car you are trying to fit the stereo into, but normaly if the wires are marked up it is easy, but if not just make a note of what wire came from where on the original and it should be relativly easy
Usually it is just a case of removing the existing radio and swapping the connections over - on some cars, such as Fords, you may need to get an adapter cable for it.
If the new unit is exactly the same shape size and fitting system as the old it is easy as described above. However, if it differs in any significant way from what you've already got then prepare yourself for hours of toil and frustration that probably won't feel like a great idea by the time you've finished.
i have a citroen saxo and i fitted a sony stereo it was the same shape and once i got the first unit out it took me about 5 mins if not less! and im a girl who knows nothing about cars/electrics and i had never done anything like that before!
How do I release a Citroen Saxo 1.1 (2001) factory radio? There are 4 small holes either side but don't appear to be screws. I can't see any other release catches. Are these possibly pressure release holes?