I moved this update from a different maybe incorrect thread.
So....I installed NEW FORD OEM 2006 spring openers 6G7Z-6343128-A on my 2005 GT this past winter. The rubber is already deteriorating, see pic. They seemed to be in great shape until a few heat cool cycles. When warm, the rubber is soft and covered in a greasy coating. When cool, it is like an old hard rubber. It is already cracking.
I went to Lowes and got a couple of options to replace the rubber. One is a rubber grommet, the other is a nylon hole plug, both fit very well. I think both of these were mentioned by others on the forum. See pics. I am trying the rubber grommet first, see how it goes. If it has problems, I will switch to the nylon hole plug.