I'm an Industrial Design Engineering student and an amateur car mechanic.
Teardowns I've Worked On
Answer to "spark plug replacement hard to reach"On the Ciera you can improve access to the rear cylinder bank by removing the plastic cover over the ventilation fan. This is held in place by just a few screws on top. It may be different for a Silhouette but it may be worth a try.
Answer to "Car goes in Safe Engine Mode afterTraction control failure"What model does it concern? I know that the XF 2.8D models get this message when a (completely unrelated) valve in the diesel particle filter fails, but this may be an entirely different issue.