My favourite element here is the hubcaps -- they add a sense of old school luxury and prestige. Most Rivs have wire wheel hubcaps, which look fake. Next is the colour -- which is rich and luxurious -- and the shape. That swept back front end and even more steeply raked windshield, followed by the formal roof. Also love the walnut veneer, and the mechanical digital clock. Of course this is not a practical, reasonable car, so the whole form factor is absurd, repeating the excesses of previous decades in a new design. It is simultaneously appealing and appalling, like so many luxury cars, and emblematic of GM's former resistance to change.
By the way, This American Life has an excellent podcast on NUMMI, GM's first effort to change it's philosophy.
