Very nicely done. I quite enjoyed reading it.
It is definately one of the better time-travel tales I've read.
The MOB didn't ever seem to wise up, even when he had his nose repeatedly rubbed in it. Snape on the other hand, while remaining in character actually seemed able to learn.
Sirius working with Malfoy was a true shocker. Not the one dimensional character he usually is protrayed as by any means.
This is one I can see rereading in the future.