Saturn gradually ceased being "a different kind of company". Beginning with the L series, its cars began to share platforms and powertrains with other GM products. If you didn't know, the L series has steel rear quarter panels as part of the unibody. I heard that as a separate company Saturn never made money. GM melded it into the rest of the company, even going so far as to ditch the Saturn UAW agreement and include Saturn in the main GM agreement. Thus Saturn is merely another division, a nameplate, no different from Pontiac, Buick, Chevrolet, and Cadillac. The Ion shared its platform with the Cobalt/Pursuit, and other overseas GMs, since it like other platforms is global. So just like those other divisions, it has models that are twin to models from the other divisions. Plastic body panels are out of the question, and let's face it, obvious benefits aside, it was really a hinderance for them. Probably contributed to the need for Saturn to join the establishment to avoid collapse.
Then there's a more recent decision for Saturn: to market Opals, do absolutely no changes to them besides the badge, in North America. Hence the Astra. They didn't even bother to change the model name! So it will be in a way a little different from the other NA divisions, but it's not too much of a stretch, since all the platforms are already shared with the NA brands.
Anyway you can forget about plastic.
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