Those plastic gears in the seat adjusters are so lame, it's like a very soft plastic/nylon which break way too easily. They aren't difficult to replace but metal would be far superior.
Motor mounts are a common replacement and I think they are supposed to much easier on the 3.6 vs the 4.6 but I still wouldn't trade it.
Blend doors become noisy after a while but mine aren't too bad, I don't use my climate control enough to be bothered by it anyhow.
Once the oil starts leaking into those spark plug wells it will eventually kill the coils, although there could certainly be other causes for it.