Does Sport Mode change the transmission shift points? I seem to be noticing that the trans is holding in 4th gear longer when in Sport mode.

Is that it's way of making it feel more responsive? I guess this is ok around town but on the highway it takes longer to automatically shift into 5th gear (overdrive) therefore affecting MPG.

Yes. I dont know the details but when im in sport mode it doesnt drop down to 5th until im at like 48mph which to me wasnt the best design. Most speed limits in my area are 45mph and ofcourse if I have it in sport mode the RPM's stay pretty high unless I increase my speed to 48mph, or manually put it in 5th. Otherwise leave it in auto mode, but I like the lower ride height and mostly rwd of sport mode.
I wish there was a customizeable mode. If there was I would have it stay in the lowest ride height setting, with shifting of auto mode, and most power to the rear wheels of sport mode, and leave traction control on :-)

James