1. MSD as in Multi Service Discount, is available where ever you purchase the Tivo.
2. Sorry, I don't know an answer for this one, I haven't seen that behavior.
3. The Premier Elite has a 1GB Ethernet port, the other Premieres and Series 3s have 10/100 ports. All the Premieres have dual core processors. So the Elites will probably be a bit faster then the other Premieres for transfers. But honestly, I think the dual cores help more.
Also, the Premieres can stream shows between each other. No Tivos that aren't Premiers have this can do this. You will probably have to do a software update and it can take a bit after that for the streaming to work.