VK Commodore (changing rear tyre size) HELP!

[Chocko Louie]

I want to change my rear tyres to 230mm or 9.054inchs.
Vk standardly comes out with 205 (for v8 or calais) not sure on what I'm looking to buy but it's either going to be an SL or Calais. If it's a SL do I have to start widening tyres from 185mm or can I start from 205mm like the Calays? Just want to get my facts straight so I have something to show the cops when they try defect me.

[MY_84_VK]

I've had both an SL and a Berlina, both with 235 tyres, and cops haven't said anything about the width, they were more worried about them being 18's but still didn't do anything, what rims were you using?