Yes, the cost of repairs has something to do with it, but who drives them and how fast they're driven also are huge factors. Here are the 10 costliest to insure -- and the 10 cheapest.

If you're shopping for a new car, chances are you're considering things such as gas mileage, vehicle size, comfort and even that all-important CD system. But have you checked on the cost of insurance?

A quick call to your agent might help you narrow your choices -- and avoid a second case of sticker shock after you drive your new car home.

The reason: Along with your own driving record, your ZIP code and the demographics of the drivers in your household, the make and model of your vehicle can have a big effect on your insurance bill, says Russ Rader, spokesman for the Insurance Institute for Highway Safety. Of all of those factors, the type of vehicle you put in your garage is the only variable you can change immediately.

"The choice of the car itself is going to affect, in particular, what you will spend for comprehensive and collision," says Jeanne Salvatore, senior vice president of public affairs for the Insurance Information Institute.

Why some cost more
Collision-damage costs are one of the main factors in differentiating the cost of insuring one type of car over another, says Rader. To a lesser extent, you also want to look at how attractive the car is to thieves.

Vehicles that top the insurance-cost list tend to be either high horsepower, high dollar or expensive to repair, Rader says. An expensive choice: "Sporty cars that are favored by young drivers who are risky drivers, so they are crashing a lot."

Higher horsepower means the driver is more likely to be going faster and getting into more accidents. That will send insurance rates up for everyone who owns a similar car.