Is the only difference between the 2.5i and the 2.5 Sport the actual sport package it comes with (i.e. just DSC and sport button) or is there more to it?
What else does the 2.5si Sport offer above these two specs?
I would guess this is the difference between the "i" and "si." So to add to what srhutch pointed out, put the "sport" in and you get the sport button (less power steering assist, different throttle response, lowered suspension etc...tons of posts on this).
Here in the U.S. the 3.0 comes as the 3.0i and 3.0si (No 2.2's or 2.5 here anymore ). Each has different HP. But you can get the "sport" package on either of them thus making them them a 3.0i sport or 3.0si sport.