Well to be honest, the standard sound I got in my 2003 V70 2.5T SE was awesome! Dolby, 9 speakers - which I upgraded (for very smal money) to more powerful speakers and 11 speakers as a factory option and was truly wonderful.
The Premium Sound I upgraded to on my 2009 XC60 D5 SE Lux was crap. Always missed the bas (didn't take the sub option).
Wife's 2009 S40 2.0D had High Performance Sound (option) which was great. Very powerful and clear.
Wife's new V40 will have Premium Sound Multimedia - we will soon find out how that is.
As a reference, I run a 9.1 system at home.....
