Just sone thoughts:I just wonder about the writings on the wall: he is mar
I mean -wouldn´t it be more plausible that anyone who is attacked so badly and feels his end is near write only the Name of the killer like Miranda did with "Roy". Why trying to use" he is..."
Could be written by the killer to confuse.....and therefore mean nothing at all?!?

RJ is wearing boots in the Episode where PJ is bound to the chair- this means he could gain or loose at least 2 cm-to all who are finding out which height the actors have- so I don´t find that useful.
About the Age: Bret Stiles should be too old-why? He is very agile and seems of biological younger Age.
Besides I don´t think that he and PJ are friends- he killed before but wasn´t touched for this for so Long( did anyone remember the Scene with Hightower-"dont push your luck".
PJ was disgussed by him .
RJ is telling PJ in the car "  imagine what life we could lead"-he is hoping for a augmention of his Situation which means that he hasn´t reached the most powerful Position (hierachy down to Stiles)