What kind of gas does a bmw 325i take?

The BMW 325 is recommended to use premium grade unleaded fuel with a MINImum of 91 octane rating as stated by the factory specs. The reason for the higher recommendation is because the engine needs the higher detonation resistance and higher air compression from the fuel. This will make Your motor run smoothly without any problems. If You use lower quality gas it can cause timing issues with the pistons which will cause a decrease in performance and fuel economy. You can also develop a ticking sound in the engine because of lower fuel quality. The gas is important to keep the recommended octane rating as You will maximize the life of Your fuel system and will keep it running efficiently.