[ShawnMarsh]

There is no question the sheet metal was thicker on older cars. 18-19 gauge was the norm, now 20-22 gauge seems to be in everything. I believe a lot of it has to do with the way unibodies are built and get their strength from having multiple parts welded together as a unit, so they can use lighter gauge and still get the same strength out of them.

The other thing that has changed is the use of HSLA in body body panels and HSS in other structural components. More yield strength PSI means you can use a thinner gauge material and get an equivalent structure, which equals better fuel economy. Today, fuel economy means a lot more than a couple MPG for the consumer, it means the car manufacturer can sell cars in the US so it's critical that they constantly improve their average.