Also is there a modern book in the Petroff that has games by Kramnik?
rrrttt, your line leaves white's dark-squared bishop and black's light-squared bishop hanging. Someone must be capturing in that line. If nothing else:
A new line of the Petroff
6.Nc3?! is not a good move. It just asks for White's queenside to be weakened, without any compensation (at least none I understand.)
Also is there a modern book in the Petroff that has games by Kramnik?