I just want to throw in a 12in box I have laying around and power a 350w amp to it. I know about how to do all the wiring EXCEPT from the stock head unit to the amp.
Does the stock unit have rca connections on it from the factory? If not, is there a harness that can solve this issue for an output?
And should I go ahead and wire up what I need while my dash is in shambles for a possible amp setup for the door speakers?
TL;DR: I have wired up stereos before, but Minis seem to be, well, very German.

 

What year of Mini?

Stock does not have any RCA's.

There is no adapter, (other than what Kevin at Integral Audio has made)

The easiest thing to do is... Tap into the connector/ wiring harness at the amp for the front signal inputs. For a 2010 or 11 MCS with HK,

Fl+ pin 38 gr/bl
Fl- pin 30 gr/br

Fr+ pin 9 bl/gr
Fr- pin 17 bl/ye

Pin 10 is remote turn on.

What else do you want yo know?

 

Tap into the x9331 connector for sound. Search front/rear channel swap for the wiring codes. You can buy a line output converter to make speaker level go to rca

 

And neither of those are required... And a lot more work.