There is no "cost" in dualism you propose.
You can have all premium models on track in the same time, up to 16 cars - with the "premium" physics - if you imply that. If you imply about actual creating a premium cars as "modeling the cars", it again has nothing to do with physics or Livery Editor.
Car modeling is done by professional experts in car modeling - 3D experts in Java, Studio 3Max, Illumiroom and similar programs.
Car physics is done by engineers and mathematicians in programs such as C, CLR, LUA or custom-made physics engines.
Livery Editor and similar details would be initially done by illustrators and game-programmers and later implemented by game assets-coders in the game-code engine and various illustrating/program tools.
Nothing of above is done by same people within studio.
Also, having all cars premium and having Livery Editor on top of that does not compromise physics in any way. Livery Editor itself is not a big deal to have in a game - in the end, "liveries" are only pixels plastered on the vehicle as separate layer of graphics on top of existing model - same as color. You can have 30.000 livery parts applied to the vehicle in the editor (as in Forza for example), but once game *renders* the car with the liveries, all of them are *merged* into one illustration that does not compromise either complexity of models or physics.
For execution of the game during play Liveries are absolutely irrelevant from performance side and has nothing to do with either physics development of time to create car-models in "Premium" quality.
In short, what you are putting as an potential *choice* or *dilemma* does not exist as such.
Problem is, the budget is not unlimited, so there are tradeoffs. You might have 10 things that really need doing in GT6 and to do them right might cost $100 Mill. If the development budget is only $60 Mill you have to prioritize and make choices. You can do 6 completely and ignore the other 4. You might do 3 completely and the other 7 half baked. Whatever the choices are, you can't do everything you want in every game.
There is no "cost" in dualism you propose.
You can have all premium models on track in the same time, up to 16 cars - with the "premium" physics - if you imply that. If you imply about actual creating a premium cars as "modeling the cars", it again has nothing to do with physics or Livery Editor.
Car modeling is done by professional experts in car modeling - 3D experts in Java, Studio 3Max, Illumiroom and similar programs.
Car physics is done by engineers and mathematicians in programs such as C, CLR, LUA or custom-made physics engines.
Livery Editor and similar details would be initially done by illustrators and game-programmers and later implemented by game assets-coders in the game-code engine and various illustrating/program tools.
Nothing of above is done by same people within studio.
Also, having all cars premium and having Livery Editor on top of that does not compromise physics in any way. Livery Editor itself is not a big deal to have in a game - in the end, "liveries" are only pixels plastered on the vehicle as separate layer of graphics on top of existing model - same as color. You can have 30.000 livery parts applied to the vehicle in the editor (as in Forza for example), but once game *renders* the car with the liveries, all of them are *merged* into one illustration that does not compromise either complexity of models or physics.
For execution of the game during play Liveries are absolutely irrelevant from performance side and has nothing to do with either physics development of time to create car-models in "Premium" quality.
In short, what you are putting as an potential *choice* or *dilemma* does not exist as such.