Yeah, there's a misconception there. You CAN release cars and tracks separately. They don't HAVE to be in a mod. Packing them into a mod is a convenient way to deliver multiple components in one package. The idea of the modID in this first incarnation is so that the components can be used online. But we already have the infrastructure in place to break these out in the future. It's not always going to be this way, but this was a safe place for us to begin.
Really, if you think about it, you could consider a modID as a pre-made list of assets for the dedicated server, which really isn't that much different than picking a car series and a few tracks to host.
We're not TOO worried about the first couple months because, other than some quick rF1 conversions there's not going to be a lot of content other than what we put out. By the time more serious work is ready to go I expect the system to have progressed a bit.
Eventually, what I see happening (and this is just my opinion based on the feedback I expect us to get) is a large repository of components--cars, tracks, UI, sounds. People will be able to download these and with a single click install them (or uninstall them, or update them). By that time I think we'll have advanced enough so that the server will send out a list of sig's that must be verified on the joining client, rather than having to rely on the modID, which by that time will be used for larger mod teams to put up full series with multiple tracks.
Or, based on feedback we may end up in a completely different direction. Point is we have this base system we're starting from and trying to stabilize, then we'll go from there. Where ever we end up it's just going to take some time...