Replacing roof 'fin' aerial

[Conquistador]

Thought I'd start this thread rather than hijack audifin's thread on a similar issue.

My car has always suffered from fairly poor radio signal (since I've owned it anyway). I can't remember who told me, but at the 2013 annual meet one of you pointed out that my roof 'fin' is in fact a Saab aerial and not an A8 aerial!

A8parts has one but in silver, not grey so I thought about finding one and replacing my current one in the hope that this may fix the signal issues and at least give me the correct aerial and I can check the roof connections while doing this, but how easy is it to fit?

Is it just a case of pulling the current one off, unplugging the connector and clipping the new one in? Or does the interior roof lining need to be peeled away or something more major?!

Here's a Saab one, the same as mine:


And here is an A8 aerial: