Does 98 Aurora Need Premium Fuel?

Need? No.

All modern cars have knock sensor ignition systems that automatically adjust to what ever fuel that is burned.

The only advantage to your car is that when you do use hi octane the engine will produce maybe 2 or 3 more horse power. Such a small increase almost no one would notice.

The only advantage to anyone is to the oil companies who make a higher profit from hi octane.

All the auto manufacturers know that people will sometimes use low octane fuels and set their engines up to run perfectly well.

So buy what ever octane you want, it will make little difference to your car but will make a big difference to your wallet!