Dr. Doom vs Lobo

doom with prep = win. period. doom with 2 months prep could EASILY bring down lobo.

Doom should win this, with 2 months he should at the least create a devise to absorb all of Lobo's power or something like that.

Doom with prep is a STOMP!

Doom, easily. He could come up with various ways to dispose of Lobo in that time. I don't know if he'd be able to kill him though, I think Lobo's still immortal.

If Doom has full knowledge of Lobo during the prep period he would fairly easily win. He has time travel and doesn't seem to be affected by aging through presumably magical means. 
 
So giving him 2 months prep essentially gives him as long as he wants.
 

Yeah, Doctor Doom is one of the few people who could kill Lobo. He could just go back in time to prevent him from becoming immortal or just kill Lobo's mother when she's pregnant with him. There's really no contest here.