Several other things can cause P0410 and P1411 codes. The SAI pump may not work, There could be a leak in the vacuum tank. There could be a leak in one of the lines or connectors that affect the change over or shut off valves. See diagram:
2.7l / 3.2l "s" 2000 And Up Air Injection In my case, it was the vacuum tank.
If you do decide to get into it, this might help:
Help Replacing the Electronic Change Over Valve - 986 Series (Boxster, Boxster S) - RennTech.org Forums