Originally Posted by c-bass

I made the mistake of asking the regular vs. premium question when I got my first BMW.

The helpful responses included:

"If you're worrying about .25 cents more a liter then go buy a Honda"

"Read the manual"

"You can do whatever you want with your car"

"I get better mileage with premium so it offsets the cost"

From my personal experience when I was working as a courier and putting about 300km a day, my M54 mileage was slightly worse with regular fuel.

Although not the most scientific method but I keep meticulous fuel records and after about 40,000km in 6 months using premium, every time I filled up with regular I would get about 50km less.

Maybe it was in my head but it also didn't feel as smooth under hard acceleration.

I'm not talking out on the track, more like stomping on the gas to pass that prick driving the John Deere harvester at 25mph kicking up rocks at you from the unpaved shoulder on a single lane country road...