[GRUNZ]

Very nice post and excellent project.
I totally agree with the fact that slotcar manufacturers are missing something by not doing a TCR category with a proper chassis.
I am also surprised that you used the slot.it 962 chassis, but the more I think about it the more I like the idea.
Also, the fact that you have "cheated" with the dimensions of the Alfa to make fit onto this chassis, I take it as a bonus: the cars should have similar performance - similar to the Australian super V8.
You did a good job with the Alfa preserving the overall dimensions (much better job that Ford did with their V8 Mustang).

 

[GRUNZ]

I have not joined the 3dp revolution although I think it is the way forward...only right now I do not need any damn hobby.
About the price point for a file: I think it depends how complex or easy to render the final object is. For instance, $5 for a scalextric border or a fence might be reasonable.
But for a car body, given that it is more complex, a more substantial price tag could be justified.
Of course, free is even better ;-)