Fraser Johnston wrote:

I'm thinking illegal. It's not like they are going to dyno it and I
will be riding it a fair way so having a fairly high average speed is
important.

Collide with a pedestrian, and somebody might take a keen
interest in the bike. I wouldn't want to shoulder all medical
costs because I was riding an unregistered vehicle.

That 200W limit is Australia-wide (enshrined in the Australian
Road Rules).

John