Here's a pic of the solenoid w/ the electrical connector/harness & vacuum lines attached from a 996. It's the same parts for a 997 and the location is as well.

Notice the black rubber 'tee' on the gray solenoid. One of the vacuum lines goes to the left muffler and the other goes to right muffler. Those lines are covered w/ the stainless steel braiding when they pass through the inside fender well to each muffler area. They are there to protect the nylon lines from abrasion and temperature.

If a vacuum line is still connected to the source you might hear some hissing. Better yet put your finger or a piece of paper over the disconnected vacuum line(s) you found. If there is vacuum you'll feel it and/or the paper will stick to it. If vacuum is present you simply need to plug those lines up w/ some sort of plug.

Since you've been in this state for years I suspect all is good.

 

Bingo....here it is

Looks like the 'tee' is gone and they plugged the hole

So last stupid question/assumption.....did cars w/sport chrono plus package not come w/the PSE button? I'm assuming when it was in it was activated by the the 'Sport' button

 

Sport Chrono equipped cars w/ factory installed PSE don't have a button. The vacuum ports are controlled by the DME. It always in the 'loud mode' w/ the exception of a speed range of approx. 18 to 27 MPH in which its in the 'quiet mode'. I believe it's a Swiss noise abatement law.

If the car didn't have Sport Chrono than a 'Exhaust Logo' button is used to activate the PSE.