Greenslips are based on driver, not the car. They are also more susceptible to insurance variables than comprehensive premiums. What this means basically is that insurance companies change the price of greenslips in accordance to their insurance payout figures for the previous year (to make up for their losses).

Driving a 1200 ute in other words has zero effect on your greenslip (other than it's a ute and therefore classified as commercial usage even if you use it privately). Your age, record, and where you live are the indicators.

Go to www.greenslips.nsw.gov.au (I think) for comparison prices.