How come nobody mentioned the fanmade mod Oblivion Lost for SoC? That thing basically reworked the game in the same way mods in general did to Morrowind and Oblivion; it's not the same without it.
If anyone's inclined to try SoC, either for the first time or replay it, give the Oblivion Lost mod a try. It's definitely, definitely worth the effort!
Are you sure that's fanmade? I thought that was all the cut content that was released by the devs earlier this year. Iirc, it includes all the vehicles that were cut from the final release, but it's also very buggy.