In all parts of the world, there are restrictions on what you are allowed to do when modifying a four-wheel drive. Sure, you can go out and buy the biggest lift kit you can find. In fact, you can put the kit on and drive with it. However, it is very likely that at some point a police officer will stop and inspect you. The correct way to modify your four wheel drive is to find out what the legal limitations are before buying anything!
In Western Australia, if you lift your vehicle more than 50mm (this includes tires, body lift or suspension lift), the car must undergo a lane change test. This is a test to see how your vehicle behaves when swerving at high speeds. If the vehicle fails, you will not be able to certify it as roadworthy. While 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, varying in price and quality. A body lift, for example, will simply lift the vehicle body off the chassis. You will end up with more room to use larger tires, but it can cause other problems. For example, if you have a bumper or a rear bar, it will stay in the same place and the body will go up, leaving a space 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 installing larger springs and shock absorbers, raising both the body and the chassis. This is not as ideal for installing larger tires, but it is probably the most common method of lifting your car.
Regardless of how you do it, make sure your vehicle meets 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 are in an accident, your insurance company can easily walk away from it all, leaving you to pay the bill. If you injure someone or damage an expensive vehicle, you may be in debt for the rest of your life!