Four-wheel drive is a system where torque is distributed to all four wheels of the vehicle. It is beneficial in some circumstances such as providing increased traction in tricky weather conditions, but is most suited to off-road driving.
This allows all four wheels to move up and down independently, providing a smoother ride when, for example, going over bumps in the road.
The turn radius indicates the smallest circular turn a car can make. With a smaller turn radius it is easier to perform a U-turn in one attempt instead of having to reverse back and forth in order to turn around.
Front-wheel drive is the most common type of drivetrain and offers several advantages. It is cheaper to manufacture (reducing the cost of the vehicle) and also lighter which helps improve fuel economy. Due to having the weight of the engine over the drive wheels it also benefits from increased traction.
A petrol (gasoline) engine offers several advantages over diesel. For example the engines tend to be lighter and cheaper than their diesel counterparts. Petrol engines also tend to have higher horsepower, and the fuel is more readily available.
Air suspension offers a smoother ride than the traditional steel spring suspension. It is also often adjustable, allowing you to raise or lower it based on the type of driving you are doing.