Your BMW is advertised as having individual throttle bodies, but you’re not exactly sure what this means. A throttle body is the housing which holds the valve that controls the air entering the engine. An engine with individual throttle bodies has a single throttle body per cylinder. This means, as an example, that an eight cylinder vehicle has eight throttle bodies. This type of an arrangement greatly improves throttle response and horsepower. Each of the throttle bodies can be connected by cable or electronically controlled to ensure that actuation of the throttle body occurs in tandem.
For more info, see How a Throttle Body Spacer Improves Engine Performance