I did mine from the top and it was pretty easy
Laid on top of the engine on a big thick moving blanket to reach the hard ones
(Drivers side near the brake booster)
You dont have to remove the grill,
I just had it off to add my intercooler for my supercharger install, right after the plug change
Here's a few You-Tube vid's that show the same method I used...
Make sure you have an actual spark plug specific socket ,
that's either magnetic or has a rubber fitting to pull the old plugs out.
You'll also need several extensions from 1.5" to 2.5"
because you'll have to add/remove them one section at a time under the brake booster where space is limited.