Missing the point.... No matter if they are the same, every detail on the car is modelled, you can see that they are actually different, rather than T10 style taking the same car and adding a different livery on it, when you can just go to the livery editor......
Come on man... They are nearly the same, no need to have 34 nearly equal cars... Is as we had the complete Mercedes C-Class (c180, C220, etc.) It's pointless. They modelled all details, yes, good, and what? They could have done other things as nobody notice any difference by seeing one of them at the time...
Dunno why you mention T10, as I haven't played Forza and have no intention to do it, nor to compare GT and Forza modelling.