A couple of miles could heat it up pretty good. I would attempt only on cool or cooler engine. A good ratchet and good socket should take them off, probably use some extra oomph. Make sure it is counterclockwise, I know you've removed others but hey we've all done something. I changed my 2010 3.0 plugs around 90k, took an extra tug to get them loose. Cold engine. Good luck. Remember a touch of anti-seize may help next time.