To prepare your car properly for a trip to the Australia Outback is an essential part of Outback safety. Having a well-prepared vehicle is more important than the question "what car to take".
Most tracks described in the Eastern Outback guide can be done with a
sturdy conventional vehicle with good ground clearance, provided that
the weather is dry.
When you take your own car, remember, a modern sports car with fancy electronics is not of much use if it really gets rough out there. Sand and dust creep in everywhere, gravel and stones might damage the bottom of your car.
The best choice is a car type that Outback folks drive. That increases the chance that you get spare parts when the need arises, even if you are in really remote areas.
If you are going to hire a vehicle, you might need a four-wheel-drive (4WD) when you want to drive on unsealed roads. Most, if not all car hire companies don't allow you to drive on unsealed roads with a conventional car, SUV or camp mobile. Yes, even AWD SUV can't be taken on all off-road tracks. To be on the safe side, ask before you hire a vehicle.
Besides, a 4WD always gives you the freedom to take a rough
sidetrack to see a scenic highlight. It is also much more convenient in a
4WD - higher ground clearance and thick mud flaps decrease the noise of
stones crackling on the floor section of the car. As proper 4WDs are
just more robust, you don't need to worry that your car is falling apart
on a rough track.
Any robust car in perfect technical condition with reasonable ground clearance. That's the secret!
In my humble opinion, the Toyota bushcamper is a great vehicle for Outback driving. It offers room for two people, has a gas stove, kitchen sink, water tanks, a fridge, and much storage.
The two 90 l fuel tanks give you some freedom in remote areas, but it is wise to re-fuel when you get the chance. The bushcamper has also a huge water tank for the kitchen sink. We never count this when we calculate the amount of drinking water we need, but it gives extra security. The bushcamper makes Outback driving truly comfortable, as long as you are fit enough to climb into the top bed :).
But this is just my opinion. There are many vehicles that can do the trip.
One more tip. If you're in a road service club in your home country, take your membership ID with you, just in case you need a towing service back of beyond. They might accept your home membership. This can save you money.
Please note: If you plan an expedition-like trip into remote and rough areas, for example the Canning Stock Route, you certainly need to do a bit more to prepare your car accordingly.
The tips on my website are designed for the easier routes in the Outback. However, never underestimate the distances between supplies and always carry plenty of water.
Have a safe trip.