Removing a car that was available for free via a workaround isn't going to really save the company any money though. Doubly so if the Silvia returns down the road as paid DLC: the backlash from the community would outweigh any and all goodwill T10 have built up with the frankly fantastic DLC route they've taken compared to the mediocre one in FM5 (tracks excepted).
My guess is that the Silvia was meant for something later on, and somehow ended up in the December title update.
