I think both of these guys will have solid years. Pennington is looking good, and McCareins will help him a lot, and be a big target in the red zone.
Porter is much the same, both the QB's the Raiders have will be looking to him as first option. He's finally the clear #1.
I'd guess that Porter will have more yardage, something like 1100 to 900, and that they're both good for about 7-8 TD's.
You live and learn - or you don't live long.