It's only logical to assume that the bigger and more expensive your car the more it will cost to insure, but that is not always the case. There may well be other factors to consider when insuring a new car.
Before buying a vehicle, get a quote on the cost of insuring it. Sports cars which carry a higher risk are likely to cost more than a larger car. Sports cars are smaller quicker and generally speaking tend to be driven more aggressively than a family car. Your age and your driving record will also come into play here, if you are under 25 and drive a sports car expect to pay more than an older driver with a good record. Luxury cars and more expensive cars cost more to insure, because they carry a higher repair or replacement cost.
When looking at the purchase of a new vehicle, check if it has safety features installed, insurance companies give discounts for items that provide driver and passenger safety.
If passive occupant restraints are installed you can save money. You can lower your cost if you insure a vehicle with full front-seat airbags or restraint devices that work automatically when your door closes. Anti-lock brakes (ABS) will also lower your premiums. You can also save if you have certain types of anti-theft devices installed in your vehicle.
Periodically and update coverage accordingly. As a car gets older and loses value, you may not need as much insurance for it. With some cars, it may make sense to only carry minimum coverage.