[M54ccibo]

Vacuum lines open the actuators on the exhaust. Once the cats are warmed up, the valves open. I am not 100% sure if they close again, but I am pretty sure they don't, and I am very certain they are always open when in M-mode.

If you want the valves opened all the time, no questions, you could pinch or plug the lines and force the valve open mechanically. Not sure that it will buy you much.