As for the audio...
2008s-2010s had two options:
Radio 9 - Two Loudspeakers
Radio 10 - Two mid range, two tweeters, one subwoofer.
2011s- have two options:
Entryline - Two loudspeakers
Highline - Four midrange (two front, two back), two tweeters, one amp, one subwoofer.
And you can always add those rear speakers to an older smart