RNS-D --> RNS-E in FL D2, but leave old Nokia 6310i phone in place?

[notorious]

Hi everyone,

I aplogize for stupid question.

I'm thinking to upgrade from RNS-D to RNS-E. My car is facelift 2002 D2. At the moment I have traditional OEM phone kit with Nokia 6310i headset installed in passenger armrest and I just love it for great reception since it uses external antenna.

Question 1: Can I install RNS-E, but leave that old OEM phone system with external antenna?

Question 2: If yes, can I also add additional Bluetooth module for RNS-E, but still somehow keep that old OEM phone system with external antenna working "together" with the bluetooth kit? Again, the reason is the benefit from external antenna which is the only thing that works in some remote corners of the country.

...I'm thinking of a switch that will allow me to toggle between old kit and bluetooth kit...

Thanks!