I don't know why Barca should get De Gea, very over-rated.
Guaita is better and would cost less too.
Guaita will be the Spanish Number 1 once Casillas dips in his peak, imo.
He's good at his feet and his aerial game/commanding of the penalty area is significantly better than De Gea.
He also can pull off wonderous saves (see Real Madrid game)