Most 6 stud paterns are the same,In these paterns the tyre industry used to have them in toyota or navara offset, mitsubishi, rodeo ect used the navara this is where i would tend to lean.As far as speed /load rating the build date is prior to this ruling open slather
The problem is once you start modifying it and needing a blue plate then you need to find out what is required? Depending on what up grades you intend on doing.You need to talk to who is going to blue plate it and ask what they want.The other option is try to contact qld transport and get stuffed around for days for some nerd to give you a answer that you cant understand because he doesnt either.I luv em people without common sense with authority.Some one in warwick will be able to do blue plates.