It appears there's some strange theories going on here!
Doesn't hold up. 100kb wouldn't even hold a single texture, MAYBE it could hold a small, simple mesh (3d model), so you're not getting anything visual for 100kb in a game released in 2011.
EDIT: It COULD hold a shader and material, though. So it might contain a new chrome paint (gold chrome, for example). But not a racecar paint scheme, not a significant track texture, etc.
This also doesn't hold up - of course the release code is going to be in there
somewhere to activate the thing, BUT a handful of lines of code do not equal 100kb, even with an installer.
100kb can hold more than enough data for the ENTIRE PHYSICS OF A VEHICLE. Easily. Consider the physics for each vehicle to be nothing more than a set of numbers - torque at every 200rpm, spring rate, spring linearity, wheelbase, gear numbers and ratios, etc. Everything the physics engine needs to know is a list of names down the left, and a list of numbers on the right.Looks kinda like this (everything after the // are comments)
var gears = 8;
var gear 0 = -5; //reverse
var gear 1 = 0; //neutral
var gear 2 = 5.3; //first
(in before the complaining about code language)
etc
etc
etc
Now, these lists are REALLY TINY. If they've managed 50kb per car for the physics, that's MASSIVE.
So, recap.
100kb files COULD contain
NO textures
NO (significant) meshes
ONE, maybe TWO Physics files
INSTALLER/ACTIVATION CODE
But what about those updates that were 300MB+? Well, there's no way in hell those were all code. Nobody updates a game with 300MB of code. It's like updating a house with enough plumbing to make 5 or 6 other houses. Out of plumbing. Those updates contained models and textures, and lots of them.
What were they for? Don't know. Some could have been fixes for holes in some tracks, some would have been replacements for the NSX taillights that people were going on about. Undoubtedly, some would have been the suits and helmets. Before we even THINK about what might or might not be on the disc, we've got 700MB of update data that we don't know much about. Sure, in among it, there could be new car models and textures, just waiting on physics and activation. But there's too many unknowns right now before people even think about figuring out what was going on half a year and 700MB ago.