When I had a PSE installed on my 2000 996 Carrera 4 the technician showed me how to make a similar modification for full-time PSE "ON". He also gave me a small plug to place in the open end of the hose removed from the actuator valve and a cap to place over the now open tube on the actuator valve. These kept any dirt from entering these two now open points and intruding into the system.

I imagine a plug in this hose on the 997S/997 PSE also would be a good idea.