RCD300 simple plug and play.
As for the Parrot kit depending on unit you have and wiring loom with multifunction steering wheel
If you are using the button module from parrot, The hardest part will be to get a ACC power otherwise it will always be on.
If you want to use the MFSW, Then get the wiring loom with Can adaptor. then you it's all plug and play.
hope this helps.