Did mine last week..
Mate,if u are currently using the original head unit.U need to take a couple of panels out.
U can't just slide it out.
When I did mine, I took off the following items:

1.Handbrake & armrest console
2.Glove box
3.Something underneath the stereo facia,where the drink holders are
4.Stereo facia

I took that stuff out because I installed my system as well [subwoofer and amp]
So basically if u are just putting the head unit in, u only need to take off the last three things above.

Hope this help