Welcome to the forums
My Engineered has just arrived at the dealers yesterday, should get a chance to go collect it next week. Ordered it in January, so been a long wait!
The Engineered and AMG Sport do have the same engine, but Engineered definitely has some tweaks done by AMG which the AMG Sport does not have.
Few obvious ones I know are diamond front grille, bi-xenon headlamps with red rings, red front and rear splitters, red calipers, tinted windows, different suspension setup, 'engineered by amg' exhaust (which sounds lovely, and makes that popping sound on gearchanges), red vent surrounds inside
Check this video out for the exhaust note on the Engineered - http://www.youtube.com/watch?v=p3-FKOOzg7A
It is a long video, but if you watch it for a few seconds at 1m 20s you will hear its note under hard acceleration, then if you watch it around 2m 15s onwards for 20/30 seconds you will hear the popping sound a good few times.
It is this video, pus hearing this exhaust note on my test drive, which made me want nothing less than the Engineered!