Snap (sort of)
Your 2007 2.5i :
http://www.nickwestphoto.co.uk/Z43.jpg
My 2007 2.5si :
http://farm1.static.flickr.com/212/4...aff43c44_o.jpg
As stated, only the si gets the sport button - there are a few other differences, like auto dimming interior mirrors and possibly a few other changes.
It's something that you won't miss if you don't have it, you'll just get used to the way the throttle is. I quite like having it behave in two distinct ways though.