At the risk of abuse, if considering ESP mod, better read NCOP (National Code of Practice) Version 2, Section 11: 2.6 at:
http://www.pharosalex.com.au/pages/33acs4.html
basically the new version of NCOP will ban
almost any modification to a vehicle equipped by the manufacturer with ESP, ESC, etc; and will disallow disconnection of ESP, ESC, etc.
This is the direction that regulation is taking. Many may disagree (including me) but insurance companies will embrace this.
Let me be clear - I don't like the NCOP position on ESP anymore than anyone else. I have a lift which would be an illegal mod under NCOP Version 2 (because I have ESP) but which I could probably get away with under NCOP Version 1. Its the adding of that section (2.6) of "No mods if you have ESP" that is going to cause problems for people. NCOP Version 2 is still open for public comment and I would hope that the Ausjeep community would jump on the chance to try to influence a re-wording of that section.