Tow Pro: pathfinder tow bar recall/mod

gday phil, i see some comment in the forum of r51 pathfinder towbar recall/mod to enhance them some how, actually what is done? why the big deal for not using wdh or lld on a r51? have seen some navara d40's (which have the chassis as r51) with a very different towbar setup and looks to me to be much stronger, why didnt nissan just do an exchange fit out!!!what type of towbar use fitted in the current caravan world red r51 with the outback jayco on it? this seems to low in the rear(given all their load inside granted. hearing back from this question,thanks for others too.