There is a simultaneous ambi slide stop option for the Compact, AFAIK that is the standard part except on the PX4CC, which comes with the low profile lever on the left side only. (beenalongtime was saying there is not a simultaneous option for the mag release, which is correct.) Here's the left side and right side slide catch levers for the Compact. I do not know whether the low profile left side lever can mate with the standard right side lever, from the pics I'm guessing not?
MGW also has the large backstrap in stock for the Compact.