Personally, I've never considered listening to music mixed with ambient road, wind, traffic, and engine noise as truly serious. On the road I listen primarily to jazz and, IMO, the standard audio system performs perfectly well.
I have listened to a standard system and the 9 speaker and both seem good. I did notice a slightly clearer sound with the 9 speakers with better highs and lows. Not really sure about which one can put out more noise because we did not blast the stereo in either case.