One detail to mention. Porsche changed some components of this system for post-99 cars - namely the E-Gas cars. Two valves ,including the check valve and the SAI valve were combined into one new part called a "Shut Off Valve" 997 113 249 90 - number 15 in the Auto Atlanta drawing linked below:
http://ffff18261f171e868c00-299409308e1e9f6b30fe104b978eef3b.r43.cf2.rackcdn.c om/108-06.gif
There is still the same Vacuum Tank that develops hairline cracks at it's base and the electrically operated change over valve.
So Particleweave how is your Test going?