I had a 2011 M3 i-touring without the bose, and had an amp/sub installed using the factory head unit... It sounded great IMO, but I recently traded in my 2011 and got a 2012 M3 i-GT with the BOSE system. I am going to have that equipment reinstalled next month. I am excited to hear the difference cause I know that there is a HUGE difference in the factory systems between the BOSE and non-BOSE.
I am looking at going with a Kicker 10" sub also... Which one did you go with and how does it sound? I want clean/crisp bass and mostly listen to pop/rock.
I would love to see pics...