my X3 audio is OK not great. It should be better at this price point, Some of the cheaper cars have better sound system, I am not sure about all other Luxury cars, i have better sound system in Jetta 09, Licoln LS 2005, Nissan Murano, and even in the minivan i owned Nissan Quest and Mercury. BMW 325i 2005 had poor sound quality, 328i 07 better but not great, 328i 2011 I got H/K premium sound definitely better, When you paid almost 50K for a car you really don't have second guess for sound system, some people assume sound system is great and did not get premium sound and had buyers remorse, people don't make car buying decision on sound but would rather add it if they knew.
2013 X3 XDrive28i Sapphire Black Premium Package, Technology Pack, CWP, SAT Radio, BMP APPS.
2013 328xi Mineral Gray, Moonroof, CWP