You can loosen the upper engine supports/mounts and rock the engine forward. This gives you a little more room.
My other suggestion is to make sure you have some bandaids handy. I celebrate when I've changed the plugs and still have all of the skin on my knuckles.
It's not that hard as long as you have a rachet that can bend or swivel. Make sure the car is cool! Sit on top of the supercharger and jam your hand down there. Change one plug at a time to make sure you don't **** up. I've never undone the engine mounts for this and don't see any reason to. Good luck.