Who are Vinny and Enzo?

Vinny and Enzo are the twin cousins of Maddie who live on the opposite, poorer side of town. They are presented as charming, cool, tough guys who do mechanic work and are not afraid to fight. Little separates the boys' apart from Enzo having sexual relations with Bitsy and an episode towards the end of the novel in which Vinny becomes unnaturally violent. The novel is not told from their perspectives.