What is the story when it comes to fitting oversized tyres to a manx type buggy? What is legal and what isn't?

Any accurate information would be appreciated.

ill be watching this two as i have accquired towdsters old wheels they are 14r x 10' up front and 15r x 13'in the rear for a nsw street legal car/baja maybe yet to be built and also wandering if my wheels are gunna be ok?

QLD rules are in here;
http://www.transport.qld.gov.au/resources/file/eb57c508de5dea8/Modification_jan05v2.pdf

It is a summary and simplified version of the rubbish that is poorly written on page 67(69) of this pdf;
http://www.legislation.qld.gov.au/LEGISLTN/CURRENT/T/TrantOpRUVSSR99.pdf

NSW rta tyre rules;
http://www.rta.nsw.gov.au/registration/downloads/vsi/vsi09_rev4.pdf

General NSW mods come under this;
http://www.rta.nsw.gov.au/registration/downloads/vsi/vsi_06_-_guidelines_for_light_vehicle_modifications_nov_2007.pdf

These codes leave some problems for VW owners. The QLD code states 1.3x the vehicle manufacturers widest optional tyre. What was the widest optional VW tyre? I've heard people argue some of the weird versions with the factory mags had 185's and therefore 1.3 gives 235's. If you have a manx there is a question as to who the vehicle manufacturer is, and if you have a proper manx with the original papers you can argue the manx was meant to have big tyres.

The rules in QLD around the mid 90's were different again, and said VW's (type 1, 2 and 3) were exempt from the normal rule and could run rims up to 7" wide.

Then some people like me have old Queensland Transport papers from when the car was first Baja'd, and it specifies bigger than normal rims.

It is all very messy. And if the new mod rules ever come in then they have some sections that should allow bigger tyres to be fitted.