Yeah i know! It's not a concious choice, just how they are.
Not sure what thermostat is in the GTR, I've not had that out, so i cannot comment other than i know it's got a triple pass radiator. If it ever comes out i'll have a looksee.
The HR31 has a factory RB26 thermostat, know that for sure. It runs between 69-72 degrees on a 20 degree day.
We actually tried another new thermostat in it just to be certain it wasn't stuffed. The motor also sits much lower in a HR31 than it does in a GTR, perhaps that is something to do with it all?
Don't have VCT so i guess it aint a problem
Temps might get up higher in peak hour stop/start type of thing. I rarely drive in peak hour that often (i walk to/from work daily).