[jmh600cbr]

Originally Posted by Barathon

It's usually best to look in the owner's manual and use what is recommended by the manufacturer. (I also wouldn't vary what you put in)

I pulled the digital manual for the 30i it says;

General information
For the best fuel efficiency, the gasoline should be sulfur-free or very low in sulfur content.
Fuels that are marked on the gas pump as containing metal must not be used.
Fuels with a maximum ethanol content of 25 %, i. e. E10 or E25, may be used for refueling.
Ethanol should meet the following quality standards:
US: ASTM 4806–xx
CAN: CGSB-3.511–xx
xx: comply with the current standard in each case.

Recommended fuel grade
BMW recommends AKI 91.

Minimum fuel grade
BMW recommends AKI 89.

If you use gasoline with this minimum AKI Rating, the engine may produce knocking sounds when starting at high external temperatures. This has no effect on the engine life.

Originally Posted by nyalpine90

i bet you get shitty performance.

I mistyped. I use the highest gas at whatever station I'm at. 91-93