Yep that is true, the best system i had was comprised of an Alpine cd head unit, a 10" rockford sub, and a set of alpine 6.5" components up front with seperate tweeter, the clarity and quality was amazing, and everyone thought i had a big build, its all about quality not quantity. if you wanna stuff 10 subs in the boot then get a Nova, some of the best competition cars run a system with only 3 speakers in them .
I on the other hand prefer the standard vw set up, it is one of the best standardsystems i ever heard, apart from the mk2 fiat puntos which have a standard sub in the boot.