Jazz b sound?

I am thinking about buying a fender jazz b or squier vintage modified jazz b because i heard many jazz bes produce this really deep crunching sound. I don't know if it is the b itself or if its overdrive,distortion,etc. Some examples of this sound is in some asian kung fu generation songs and in Robert Trujillo in Metallica, especially the live version of "For whom the bell tolls". They both use bes with 2 single coils, one mid and one bridge. So i was wondering if they were distorting their sound or if its the bass' natural tone.