Well you could run quads, so long as you had a plenum and an airflow meter.
You could change the airflow meter to another one too, change injector sizes etc, but it's not as flexible as you'd think.
There's some versions called D-JETRO which interface with a standard BOSCH MAP sensor instead of the factory airflow meter or map sensor, but it doesnt appear that one of these is available for the altezza.