An assembly can include a turbine housing that includes a bore, a wastegate seat and two wastegate passages that extend to the wastegate seat; a rotatable wastegate shaft configured for receipt by the bore; a wastegate arm extending from the wastegate shaft; and a wastegate plug extending from the wastegate arm where the wastegate plug comprises a profile defined in part by a portion of a torus, for contacting the wastegate seat in a closed state, and defined in part by two plug portions, for defining clearances with respect to the wastegate seat in an open state. Various other examples of devices, assemblies, systems, methods, etc., are also disclosed.