plenty of such systems originaly comes in cars in europe.My father drives 1998 originaly french market nissan primera with liquid lpg injection.System got a pump in tank, small valve for pressure control under hood, and injectors driven by ecu, wich takes pulse from oem ecu and transfers signal to lpg injectors.Almost ten years trouble free system.Nothing special actualy - driveability is not any different from gasseous state injections.