If the deal is approved by antitrust authorities, Polytec will gain access to South America and China via Peguforms's production site in Brazil and its joint venture in China.
Polytech estimates the two companies will have combined annual sales of about 2.2 billion euros (22.02 billion yuan). The merged company's top customers will be Seat, BMW and Volkswagen.
Polytec, which is based in Hörsching, northeast Austria, produces door panels, headliners and engine parts for customers such as BMW, Mercedes-Benz and Volkswagen.
Peguform, based in Bötzingen, southern Germany, makes bumpers, front-end modules, cockpits and door panels.
According to Huemer it is not yet decided whether one of the companies will have to change its name or - if they decide to have a common name - which one will be chosen.
Cerberus, which took over Peguform in 2005, also has majority control of Chrysler LLC.