Rear wheel track 2010 370Z?

Eugen

Hi all, I've recently bought a used 2010 Nissan 370Z Auto Coupe from QLD and i tried to register it in Canberra but they knocked me back, twice, because the rear wheel track is too small. The original owner had put 20" x 8.5" aftermarket rims on the front and back and sold off the originals, so i bought some 10" wide +40mm offset versions for the rear wheels that i was told would be alright, apparently they are not.

My rear wheel track is currently 1530mm and the rego guys say it needs to be 1550mm, but the guy from the wheels shop says it only needs to be 1540mm after ringing around and doing some research. Can anyone confirm for me what the rear wheel track needs to be? or have a set of original rims?

any help would be appreciated,

Eugen