Long time lurker here, hopefully I can shed some light on this run. I was one of the first people to bring Super Off Road to the speedrunning community and
my run from Extra Life 2013 is the one where I laid out the "rules" for the speedrun that have become the community standard.
I went with "Max Upgrades, 99 Nitros" because at that point there is nothing left to do in the game (other than race on tracks you haven't seen yet). The track pattern is fixed, it is not RNG. There are 16 tracks in the game each with 4 permutations for a total of 64 total tracks. (Forward/Backward and Forward/Backward with hay bales.) The reason I didn't go with 64 tracks was because you will start to see duplicates before you reach the 64th level. I forget the exact number, but you won't see the final "original" track until 70-something levels have passed.
Item spawns are "random" but in a TAS I am certain they can probably be manipulated. The location they appear in is chosen at random from about 2-4 different possible locations per track. Some of them are better than others (e.g. on "Redoubt About" the item spawns in the upper right which is not optimal, there is a far more optimal spot on the inside of the large turn.)
The reason the runner goes with Tire upgrades first instead of Top Speed is because upgrading tires reduces the effect that different kinds of terrain has on your truck, so it's an overall better time save through efficiency of your vehicle rather than blasting at maximum speed and getting slowed down by water and sand.
That said, it's an honor to see a speedrun category I came up with get the TAS treatment. Kudos jmosx36! :)
