1. I think Pre-Comp is when you really start dropping volume and upping intensity and Comp. is when you start working on race pace and such.
2. I know that, but I don't like the idea of doing SHORT sprints off time, long ones are a different story. Sorry I didn't clarify.
3. I'd say run the timed sprints at near-max speed since you're trying to cover the longest possible distance in the allotted time.