Changing the radio: adapters needed?

I want to upgrade the stock Blaupunkt radio/cassette player of my K11 to a Sony CDX-GT24 cd/mp3 player. I've read that the K11's wiring is not ISO standard and that the car audio earths through the antenna.

Looking at this installation guide of the GT24, I think it comes with all the adapters (ISO and antenna) I'll need, but I'm wondering if I'll need any more.

Can anyone tell?