Ford recommends a light coating of silicone dielectric grease inside of the plug and coil boots. So no need to worry. Plug wires/boots will swell and disintegrate from petroleum products, such as motor oil.
Confirmation! I wrote to Permatex and asked if their Dielectric Tune-Up Grease will degrade silicone rubber products. They wrote back - same day! - and assured me that their product will not degrade any rubber product including those made of silicone rubber.
So with the assurance of the manufacturer, a valued Ford tech, and no particular stance by MDS, I installed my new MDS spark plug wires yesterday. Unlike the sparkplug installation, I managed to do it without removing either the intake plenum or the front tires. But next time, if there is one, I'll do the spark plug change and the spark plug wires in the same effort. It's not easy work, the confines are tight, and there are lots of things in there that will scratch and cut your hands and forearms. I am VERY glad that I bought a sparkplug boot puller!!!
The MDS spark plug wires (P/N 31639) fit perfectly. They might be a small fraction longer than the factory wires, appear to be of very good quality, and are easy to manipulate. The wire hold-downs provided are not compatible with the pegs on the valve covers, but the original wire hold-downs can be reused. It's a tight fit to get the MDS wires into the factory hold-downs, but you can make it work if you have a strong thumb.