Summit diff lockers will explode if you put brushless to them.

The diffs will handle it just like regular Revo Diffs will. Fineish on 4S, explode on higher. You need aluminum cases and diff cups to really hold up on brushless. Cases are available, but won't fit the Summit (locker hardware won't fit), and cups are available from Germany for around ~90$ each.

The trans will handle the power, though.

In short: Put a 820-Size DeWalt 14.4v motor in if you want more power in the Summit. BL just trashes them.