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"Interbuildability." It's a word GM vice chairman Bob Lutz coined to describe the ability to build a variety of vehicle types off the same platform. It's also a description of GM's vehicle road map. Though not a word that easily rolls off the tongue, the concept behind the word will have lasting effects on GM's future product portfolio.
"The next-generation Epsilon platform will be more flexible and able to support a wide variety of vehicles," says Carl-Peter Forster, president of GM Europe. The list includes, but isn't limited to, sedans, wagons, SUVs, and vans spread among the Chevy, Daewoo, Opel, Saab, Pontiac, and Saturn brands. "Interbuildability will free-up resources, allowing us to create more choices for the customer, eliminate the need for double tooling, and allow GM to balance production worldwide." Whether that last item includes things such as building Saabs in China rather than Sweden, Forster wouldn't say. However, he did say that European volume manufacturers will have "to go farther on cost," and this includes "having the right production footprint." Judging from GM Europe's willingness to add Opel Zafira minivan capacity in Poland, not western Germany in order to cut costs, there can be little doubt that Saab's Trollhattan, Sweden plant—which boasts a capacity utilization around 50%—won't have much time to fix things.
Oddly, the current Epsilon platform shared between the Opel Vectra and Saab 93 in Europe is not quite a world architecture. Says Forster: "It deviated during development to a point where the Opel and Saab models are similar, but different enough to prevent us from producing them in the same plant." He contends the new version—just beginning development at Opel's Rüsselsheim, Germany, headquarters and due in the market before 2010—will let GM build any variant at any plant assembling an Epsilon vehicle anywhere in the world. "You are free to decide where you want to build the vehicle once you have interbuildability," says Forster.
Forster sees no image problems arising out of the move to produce vehicles that are mechanically similar, but stylistically different. "People buy cars, brands and dealers, not architectures." Therefore the next-generation range-toppers at Saab and Opel will share the same architecture and have some overlap in size, but will not compete for the same buyers.* "Look around the industry," he says flatly, "there are amazing similarities among cars in a class in terms of chassis and powertrain. It's the execution, design, tuning and vehicle concept where differentiation increasingly will take place."
* Forster says the next generation Saab 95 could be built on the current Epsilon, Epsilon 2 Epsilon widened, or Sigma architectures. It, however, may not be the top of the line. A production version of the rear-drive Opel Insignia show car may be on the road by 2007, and will include variants from both Saab and Cadillac.