its hard to interpret transmission feel through words,

As I think it states in your owners manual car should be stationary when going from reverse to drive and a moment should be given for engagement.

but drive to neutral should be quiet - try it with your foot hard on the brake pedal and see it you notice any difference

test drive another S to compare -

where are you feeling the heat from the transmission? tunnel carpeting?

what speed and outside temps for the ten mile heat build-up?