Spark Plug change in an '04 Durango

I would like to change the 8 plugs in my Durango next time around.
This is a cost-cutting measure, since the shop really charged me a
bundle. I noticed they have some sort of cap or device on top of each
plug. In fact, the rear two seem to go back into the fire wall a bit.
It looks like I can get to it, but I would hate to remove a bunch of
stuff first.
How difficult is this job? I have changed plugs in my '93 Dakota but
they are easy, wires, easy access, etc. My concern also, is will I
throw a code with the engine if I do it myself?

Any advice would be great.
Leo