I too have insurance with Allianze with no issues, although I no longer have the DII insured through them.
They will cover modifications to a 4wd and had no issues with any of my modifications until the total lift was greater than 75mm.
They will cover you anywhere in Australia, public or private as long as your not breaking the law.
75mm is the limit of their cover for 4wd modifications so I have now gone TCIS.
I sourced my Allianze insurance through the NAB.
I still have the other car and house insurance through them.

