The ones I have / were given are NGK PFR7S8EG but I have no idea on temp range I'm afraid? Its nowhere on the packaging however I have just checked the NGK website and they are the ones listed for my vehicle. The website says that they also come pre-gaped for the specific vehicle so I suppose that answers part of the question.
I'm still sure its pulling different than before though. Been driving it today and it definatley feels like the peak torque has move up from around the 2, 2500 rpm to more like 3000 rpm but it pulls loads better at high revs? Its completely bamboozled me!