wannabe2

Hi all,
I have a 2010 A6 Avant with MMI 3G (not 3G plus) but without navigation. I'd like to see if the car was pre-wired for it, and from the reading I've done one of the things to check for is a NAV wire coming from the shark fin antenna that terminates in the C pillar (?) and isn't attached to anything (just a coloured connector), that would normally plug into the NAV unit.
1) Can anyone confirm that it's the driver's side C pillar where this wire/cable would be?
2) How do I get the trim pieces off the C pillar to see if the cable's in behind? The interior trim pieces fit very tightly with few visible fasteners, and I don't want to damage anything.
3) What is the part number for the NAV drive I'd need for my car?

Thanks