In all parts of the world, there are restrictions in what you are allowed to do when modifying a four wheel drive. Sure, you can go out and purchase the biggest lift kit you can find. In fact, you can fit the kit, and drive around with it. However, there is a good chance that at some stage a police officer will pull you over and inspect it. The correct way of modifying your four wheel drive is to find out what the legal limitations are before you purchase anything!
In Western Australia, if you lift your vehicle more than 50mm (this is including tires, body lift or suspension lift) the car needs to undergo a lane change test. This is a test to see how your vehicle performs when swerving at high speeds. If the vehicle fails, then you will not be able to get it certified as being roadworthy. Whilst some of these rules seem over the top, they have been put in place to protect road users.
There are many different ways to lift a vehicle, ranging in prices and quality. A body lift for example, will simply lift the body of the vehicle off the chassis. You will end up with more room to run bigger tires, but it can cause other issues. For example, if you have a bumper or rear bar, it will stay in the same place and the body will go up, leaving a gap in between the two. Other issues can be radiator hoses and gearbox levers, as well as the need to lengthen cables and other hoses under your vehicle.
The most common way to lift a four wheel drive is to install a suspension lift. This means fitting larger springs and shock absorbers, lifting both the body and the chassis up. This is not as ideal for fitting larger tires, but it is probably the more common method of lifting your car.
Which ever way you go about it, make sure that your vehicle is going to meet the criteria that the law specifies for your area. This will often vary from state to state; check it out! If your vehicle is not legal, and you have an accident, your insurance company can quite easily walk away from everything, leaving you to pick up the tab. If you injure someone, or damage an expensive vehicle you can be in debt for the rest of your life!