You don't say which year but if it has an amp, then it sounds the same as my anniversary was.
If it has the standard connectors, then you can bypass the amp (modern head units are all-in-one).
Turn off ignition
Whip out the radio and have a look, there should be a couple of rectangular plugs (about 30x15 mm) in the back of the unit and another plugged into a socket on the wiring.
The plugs have offset clips on them so you cannot plug the wrong one into the wrong hole.
Once it's all unplugged, plug the relevant connectors into the matching sockets on the new head unit.
Fitting mine took about 5 mins.
Disclaimer - all at your own risk (If a previous owner has completely bu**ered up the wiring then you could blow a fuse or worse)
