1.Combine sauces and sugar in medium saucepan; bring to the boil. Remove from heat; cool marinade 10 minutes.
2.Place pork in large shallow baking dish, pour marinade all over pork; cover, refrigerate 3 hours or overnight, turning pork occasionally.
3.Drain pork; reserve marinade. Cook pork on heated oiled grill plate (or grill or barbecue) about 30 minutes or until cooked through, turning and brushing frequently with some of the reserved marinade.
4.Boil remaining marinade in small saucepan about 5 minutes or until thickened slightly. Slice spareribs into portions; serve with hot marinade.