Of course you can do it by just removing the coil packs, but if you value your skin, remove the valve covers.
( Also allows you to be sure the new wires connect to all 12 plugs securely )

When I first installed my Magnecor's, I did it with the valve covers on, a couple of years later I swapped out for black crinkle painted covers and checked all the wires while the covers were off.
4 out of 12 were not fully seated.
Those Magencor's are squiggly suckers !