the brackets gone do help. i stand at the pass side fender and reach back there, im also a tall lank. so i got no need to climb on the engine, those pics blow my mind every time lol
the one plug blocked by the o2 sensor, put just the socket on the plug, then you can just get 1/2 the tip of a 3 inch extension in the socket, break it free then turn the socket by hand. replace the same way.
if your using a real plug socket, its got a nut on the end of the socket, you can use a open end wrench on it too.
since headers and pull brackets gone a plug change is silly easy, no moving the engine or nothing, just reach in and get em.