Good article.
As it says GM needs to hurry if they plan to have a vehicle in place for the stated 2017 Oz plant closings.
They don't say it in the article, but GM would have to produce the SS with other (smaller) engine combinations. In order to make this whole thing feasible GM needs find a way to raise the production numbers (economy of scale) To help meet CAFE numbers they will need to offers higher mpg models. The higher mpg models will appeal to a broader spectrum of buyers resulting in higher sales.
GM needs to forecast sales figures of at least 100,000 units to make it feasible to set up production alongside an existing car line (Oshawa perhaps). To have its own plant GM needs to forecast sales of well over 250,000 units per year. These numbers are based WAGs using my 20 years of GM plant experience.
My SS is a great ultra high performance large sedan, but will Joe Sixpack pay $30,000 for a de-contented 4 cylnder tubo SS Jr?
That is the real question...