Wow lots of topics, lots quick responces, and lots of strong views.

My turn
If it doesn't have the FACTORY warrantee, it's a modification.(although none of the bathurst cobra "bits" were warrantee'd).
In my opinion that's the easiest way to do it.

Regos (my perfect world)
Regular rego- Australia wide, and green slip part of your licence.
Historic rego- Australia wide, STOCK, cheap, limited to club events.
Modified rego- Stringent pink slip, 50 days a year use, logged with the RTA/RMS (etc) via their website.

And by stock I mean as that vehicle left the dealership. It annoys me the amount of fake GT's that have Historic rego. If they were built as white 6 cyl column shift fairmonts, they shouldn't have rego as 393ci electric blue GT's.