Kiwiaudio

Im considering either the Grom BT3 or a GTA car kit.
Somewhere in the Grom explanation, it says the Sirius service must be disconnected. Doesnt make sense to me as the kit is selectable using the cd changer input. I cannot find an explanation for this and its a deal breaker if it is indeed the case. I have not pulled the radio yet, but the port on the back of the radio that these kits plug into isnt used for sirius, is it ?
The Grom is available with two different firmwares and i think the SAT emulation version firmware will require this. Only thing that makes sense.
Im sure a lot of you use these kits. Hopefully one of you can shine some light on this.

Edit: after digging a little more, the CDC version of the Grom is the one to get. It retains steering wheel controls and doesnt mess with the Sirius service. Is this correct ?