Be careful with the credit card 'trick', I never managed to get it to work when I tried it, ended up bending the clips out (not irrepairably) in doing so :-s
Luckily knew someone that had the proper tool from a Golf Gamma head unit... which again I think is similar but not perfect as that didn't work as easily as it should have done...
As for the changer, you'll need to pull off the surround then there's two torx screws and that's your lot.
Rob