a quick lesson. it is the gear ratio of the transmission that determines the RPM at which a car runs at a certain speed, NOT its power. I'm assuming that the gear ratio of the sport shift is very similar, if not identical, to the old automatic, therefore it runs at similar rpm at the same speed.
All that 8 extra horsepower gives you is it allows you to REACH that speed/RPM in shorter time, but it does NOT decrease the RPM at a certain speed. The gearing of the transmission determines the RPM of the engine at certain speeds.
so remember, in the relationship between RPM and speed, power has no direct effect to it.