It will run on 91 octane unleaded just fine, but it is strongly reccommended to run on a high octane like 98 or similiar.
The BMW 323 i takes Premium gas,but can use mid grade as well. premium is preferred.
Super or 93 Octane
Unleaded, with as higher octane as possible (but obviously not race fuel).
Regular gas is just fine for a 1999 model year vehicle.
Regular unleaded.
55 ltrs (1997 323 hatch)
The 2007 BMW X5 is a gas-powered vehicle.
The 2004 BMW X5 is a gas-powered vehicle.
The 2014 BMW X3 is a gas-powered vehicle.
The 2010 BMW M5 is a gas-powered vehicle.
The 2011 BMW X5 is a gas-powered vehicle.
The 2010 BMW Z4 is a gas-powered vehicle.