Oh right, I must have a different handbook to you then?
You are right, my motorway temp is about 110 deg, but only if Im going 90+, I thought that was fairly normal? - If Im cruising at about 70 to 80 then it stays around the 100 mark.
I used Castrol GTX Magnatec before and it ran rougher and hotter on that, I changed to Mobil 1 because my handbook says 15w50, and Id heard it recommended on here.
May have to consider changing again.....