I went for the best audio system available as sound quality is very important for me. I therefore have the Burmester system fitted in my 718 Boxster S. It certainly sounds far better than either the stock system or Bose options, but despite Burmester being a high end audio company it still sounds far inferior to a well sorted domestic audio system.
It always surprises me that so many simply equate more expensive audio with louder though, as Shark stated that is not the point at all. Better quality electronics & loudspeakers generally equates to improved sound quality. Having additional power means more control, more refinement & less distortion which enhances the replay quality, but actually has very little overall effect on volume with any given loudspeaker (it has some, just not as much as many people seem to think). Double the amplifier power doesn't mean double the volume, in fact far from it. Take a loudspeaker sensitivity of 87dB per 1 watt for example. To get an increase in volume of 3dB requires double the amplifier power (the human ear has difficulty even being able to detect change in volume of less than + or - 1dB). To increase to 93dB requires doubling the power again etc etc.
1 watts = 87dB
2 watts = 90dB
4 watts = 93dB
8 watts = 96dB
16 watts = 99dB
32 watts = 102dB
64 watts = 105dB
128 watts = 108db
256 watts = 111dB
512 watts = 114dB
An increase of + 10dB is required before a human ear perceives something to be twice as loud & yet doubling power only ever brings a 3dB increase.
Compare then the example of Car (A) fitted with 100 watts of amplification.
to Car (B) fitted with 800 watts of amplification.
The common misconception is that the stereo in car (B) will be many many times louder than (A), after all it's got eight times the power, but assuming everything else is identical it's actually only 9dB louder, or as the human ear perceives it not even twice as loud.
What that additional power actually does is hold the loudspeakers in a vice like grip, so that when for example a bass note is hit & the loudspeaker driver is forced forward, it then gets pulled back in immediately. This brings extremely sharp definition, punch & clarity. Compare that to the lower powered amplifier, when the same bass note is replayed the loudspeaker driver is forced forward but the amp has an overall weaker grip & the loudspeaker driver flutters a little before returning. That produces a tubby, flabby, distorted sound, lacking overall clarity. Also, assuming both stereos in both cars are playing at exactly the same high volume, you are far less likely to damage your loudspeakers in the car with the more powerful amp set up because quite simply it distorts far less.