Originally Posted by Irish-Texan
Here's my reference point on our 28i X1 xDrive MSport.
1200 miles in and getting just shy of 28mpg in mostly highway driving.
Given that you're in TX, you can probably get 91 octane gas?
If using 89, you'll get worse fuel economy, due to the engine readjusting to avoid knocking.
Also, depending on where you live, you may be able to get ethanol-free fuel, which will also improve mileage (E10 has around 5-8% less energy than ethanol-free fuel)