125 Primavera 1968-1983 Carburetor

My DellOrto SHB 19/19 carburetor has a broken quarter section where it fits into the manifold.  I need a new Carburetor.  The engine is stock as far as I know.  I do have a Leo Vinci exhaust.

Is there any advantage to buying the Polini 19 Carburetor over the DellOrto SHB 19/19?  If so what would be the benefit in performance.  Would I need to buy a new manifold also if I bought the Polini 19 carburetor? 

Most easy way for an engine which is stock would be the Dell'Orto carb.