ColinL - I've met some prtty dumb engineering in my time.... LOL, No really - I think that it might transfer more road vibration and they wouldn't want this, plus foam DOES cost something and since they went so far as to cut the cost of the f**king trunk light and switch, I'd expect every teeny tiny corner cut that they could.
In truth, what Subaru needs is a plant in the US making Impreza's... talk about cost reduction, they wouldn't have to import them anymore and al lof a sudden they'd be priced like Civic's. Honestly, there is very little difference in the engineering of our cars to Hondas, except the fact that ours are made out of the country and have to be imported. The materials are the same, if not cheaper in the Impreza (soft plastics, cheap tires) so I'd expect it to cost a lot less then it does now, personally. *shrug*