Oh the Finnigans will wipe the floor with the Gianellis. The Gianellis are weaker by far, so I think the Finnigans should attack first. Though, I have to wonder what instigated this whole thing - if the Gianellis are the aggressors, they'd probably do so from an ambush. Maybe at a meeting with Rowena O'Malley or something. They'd try to strike hard and fast. Even though Rowena O'Malley isn't exactly on great terms with the old guard, the Ciarniello Family has a lot of the old guard under the thumb of Numbers Ciarniello. The real difference-maker in a war like this would be who Numbers sides with. Traditionally he stays out of these kinds oft things and sides with the winner. But in the past he sided with the Bigios, who later became the Gianellis, so he might be willing to take up arms against the Finnigans.