Make a simple research : impala 1977 and impala 1985 in google image. The differences are obvious. Same for the Caprice and if you're curious, Delta 88 and Regency. Cars share the same platform from 1977 to 1985 but no common metal sheet between a 1977 and a 1980. For the wheel pack in the same time as the Olds update which is when it's ready. Impala Wagon was just added, with the simple seats of the Custom Cruiser (rear bench is different from the Sedan, more vertical). This car will replace the base Caprice Wagon, there is no need to have two different base wagon. I will do the same for the Impala Sedan.