It isn't impossible to do plugs on these without yanking the motor cover, but you will most often anyway to look at Cap and Rotor, Wires, etc. I have found the slight extra time involved putting on the hoist and pulling wheels, and the splash shields, results in doing the entire spark plug swap in less time then doing them through the motor cover (and results in less knuckle damage)

After you get the wheels off, remove the plastic retainers (don't break them) attaching the splash shield to the inner wheel tub area and you will see how easy this will make getting to the plugs. It sure makes it much easier to remove wire boots that seem welded to the plugs.

Here's a close up view of the pass side. This side isn't bad from inside through the motor cover opening, but its a lot easier here.

The drivers side is a bit more cramped, but its much easier here then through the motor cover opening, you will need to pull the back two boots from underneath, still easier.

Number five seems the worst here, but if you approach it from this angle, its a snap.

Here is my long plug installing tool, an old antenna mast with a boot on the end, safer than using your long extension and plug socket and maybe starting the plug incorrectly, I use it mostly for going in through wheelwells. This can be done on lot of different makes, models, and years, if it looks tuff to do from the top or inside, this may make it a lot easier and, even if you spend the extra time going on the hoist and pulling wheels, it will probably result in less total time.

A closer view of my plug tool, you can really see it works.

About 30" long. Time to put on hoist, 3-5 min, pull wheels, 2-4 min, pull retainers on splash shields, 5-8 min, swap plugs out, 12-15 min. Try it if you haven't already, and if the boss will allow it, you won't go back.