After Westy`s input on his doubts on the `superior` sound from DTS soundtracks, I found some useful info sites.
For details on the low/high bitrate (754/1509kbs) DTS soundtracks, try this (although it isn`t up to date so anyone know a better one)?
http://homepage.ntlworld.com/bwescombe/dts_dvd.htm
For details on DTS v`s Dolby Digital try this (and by the way Westy...you WERE right!):-
http://home.clear.net.nz/pages/adbarr/page1.html
Very interesting, including confirmation that the two sound formats should be virtually indistiguishable under identical mastering conditions and also explains the 3-4db difference in volume between the two formats!