I just did it also. I broke one of the round clips on top of the coil pack. I felt badly about this until I did the other side and discovered that a dealer tech with supposedly all the right tools had broken one of the round clips off the top of a coil pack on that side.
I was using the backyard mechanic method of removing the coil packs, rotating them a little to hopefully loosen up the boot on the plug and then levering the pack out with odd tools from my tool chests. Next time, I may plan ahead and make that PVC plumbing tool . . . although it will now work on only 6 of my 8 coils.
No need to touch the plenum. Just pull the air box on the driver's side, unclip a couple of hoses, and remove the cover over the coil packs. On the passenger side, just loosen the coolant reservoir and move it aside and then pull off the cover over the coil packs. The covers tug off.
The coils were a bit of a pain as noted above. I first disconnected all the wiring harnesses and then I tried to loosen them by rotating them and then I levered them out. For reinsertion, push until you hear and feel that suction snap as it pops fully into place. You will know.
The plugs were easy except for the ones closes to the firewall. Those take more time. On the passenger side, I had to drop my plug socket down the hole and then drop an extension into it. U-joints might work. With patience it is doable. A bendable magnet tool would have helped pull that difficult one out. I used a 3/8 ratchet with a long extension for most of the plugs and a short extension for some of them. My spark plug socket is a very long socket, however, as spark plug sockets go. It helps to have a newer plug socket, the kind that grips the plug. Otherwise, you may have to use a magnet tool to fish the plug out.
I did use a little never seize on the plug threads. I always do. And I tightened them to good-n-tight. I have been working on cars for 30 years.
Took me less than 2 hours start to finish, which is not bad for a first timer on this job.