What's the deal with this 660 SMC?

Went by the local shop and saw this, the first time I've seen one. It was sweet! A few questions:

How does it differ from the 640 SM? A bit more cc's I assume, but is the bodywork different or the same. I noticed the 660 has a tail light but is there a hookup for a headlight? I realize it's a competition bike as well but if I can hook up a headlight I can do many things with it? I forgot to check if it had an electric start. What else is the difference between the two?

I think I'm in love!