550 / 575 mix-up

Does anyone have some simple tips on how to keep a 550 and a 575 apart, because i saw one of them a while ago and I could tell wich one it was so i felt really stupid; :-(

The front grille is the easiest way to tell them apart as the 550 grille has fog lights at its sides while the 575m doesn't.

Pictures from cavallino.cc Head over there (link at the top of the page) and browse through the 550/575M pictures to see other differences. They are not many, but there are some.
550
http://www.cavallino.cc/photos/cars/550maranello/550maranello_hr1e.jpg

575M
http://www.cavallino.cc/photos/cars/f575mm/f575mm_hr1h.jpg

Another way you can tell is the outer bulb of the front headlights is different. in the 575M, the bulb is a small, orange circular one, whereas in the 550 it is a |) shape kinda, and is white, and is noticibly different looking.