Want a real upgrade
my car only has stock cd player and two HK stock subs. I want to put two 12" subs in the trunk for now or an amp later. I have seen a M3 with stereo upgrade. and it has 4 switches near the sunroof switch. it looks really nice, but, I can't find the pics again. can anyone show me some M3 with very nice stereo upgrade?
and brands you guys would recommend?