Broken Timing Belt, '03 ST4S

Welp, pulled the covers today after the motor went out on the highway, and it would appear I'm screwed. Belt has broken on the horizontal cylinder.
So what damage am I possibly looking at? Valves, guides, etc? I'm new to working on the desmoquattro (LT's guide is on it's way), these are interference motors, correct? Possibly a chomped up piston?
Give it to me straight, doctors.