Most of the SE's have the bottom part of the bumpers painted, but not all. Depends on the colour. HID's are also another visible difference on the outside. In Canada, you have to get an SE to get HIDs.
You know what they say about gambling.... You just keep winning until it's all gone!
Many SL's have HID's here in the US. It seems that when the SL's have the HID's they also have the lower bumper painted that dark grey color too. So, the wheels are the only obvious thing. I've debadged mine now, but the 6 spoke wheels still speak "SE"