Help with new sound system DS3

[Nemie]

I want to add a sub and a Sony head unit plus front/rear speakers, below are my concerns.

My car is a Citroen DS3 1.6 THP D Sport Plus.

1: Can I remove the default cd and replace it with a Sony head unit? without losing the info screen data option, as it seems the controls for that screen are built on to the cd player?

2: Will I lose the reverse meter?

3: What type of adapter would I need for the Sony to DS3 plugging sockets?

4: How can I disconnect the DS3 Sub in the boot of my car, from what I can see it has a fitted carpet around it, and if I disconnect it would it break the circuit for the speaker wiring system?

5: Anyone have a link to the wiring diagram for the speaker system for the DS3 1.6 THP D Sport Plus 2013?

6: Any known hole/gap for battery cable inside to battery engine bay?

Anything thing other that might help with this install please advise.

Thanks.

[wurlycorner]

For question 3 - this adapter should suit.
https://ebay.us/m/577wqX

Alternatively, if you want to retain steering wheel control and other display functions (to answer some of your other questions) then spending a lot more on this should work:
https://ebay.us/m/rPFQ7X

[Nemie]

Thanks I will consider option 2 if option 1 causes a EML fault, so will order option 1 for now.

[wurlycorner]

I doubt option 1 would cause an EML. It would just mean you lose some functionality on the display and steering controls.

[Nemie]

I just added the Sony head unit to the car and the sound was a huge improvement, no new speakers have been added yet.

I went with the cheaper adapter option linked by wurlcorner but bought from Halfords so as not to wait, it works fine. I have lost the option to set time and the trip screen, I also have lost sound for the reverse warning but the screen display working fine. No EML

Peugeot/Citroen ISO Harness Adaptor - CT20PE02
and
Fakra FM Modulator Kit - CT27FM02

Type CT number in Halford search.

Waiting on lead for Subwoofer please look at question 6 and 4.

Front door Audison Apx 6.5 arriving tomorrow if good will get another set for rear.

[wurlycorner]

For question 4, I would expect if you unplug the standard sub, it would have effect on the rest of the sound system - all that would continue as normal.

[Nemie]

Question 4 how to get to the boot sub, took a lot of looking but found a video.