This video is essentially a PR piece for General Motors but it does have some nice footage of M5 light tanks and other vehicles running around at a proving ground. One thing worth noting is that the model vehicles built for testing suspension designs shown in the video would appear to have nothing to do with the M5 light tanks shown later in the video. The models shown appears to simulate individually sprung road wheels, unlike the volute spring system on an M5. Our best guess is that this model is part of the early design work for the program eventually leading up to the M18 Hellcat tank destroyer, which was built by Buick.
Here is the model from the video:
Here is the T49 gun motor carriage: