For the sake of this discussion, let's say it cost $3 billion for a great architecture with five variations on a chassis them rather than $5 billion for five decent chasses.
That would leave GM $7 billion to spend on better mechanicals and superior accommodations for the five models, rather than the $5 billion under the old system.
In today's competitive stock market, of course, GM would probably save a billion of that and spend $6 billion on the products, but the point is still made.
A fine principle then, in theory, but how does it play out in practise?
Well, having driven various models of the Opel over demanding roads around this former Olympics site, I can tell you that it's resulted in an improved Vectra for Europeans and, more germanely, a much better Malibu for Canadians.
It it were up to me, I would simply bring the Vectra as-is to this continent and let people enjoy the serious abilities of a European touring sedan.
Stefanyshyn has actually considered this, since there is a healthy appreciation among younger North American buyers for German cars. But for various marketing and political reasons (like who would sell them, and exactly how cranked would the CAW/UAW be with GM for importing cars from Europe?) it isn't likely to happen.