Ciao Pilou!
Yes the files starts to be quite big doing istances.....but i will duplicate objects on the rendering program....here on Moi i'm modelling just some assembly (brake kit, wheel kit) and i'll do the top assembly on rendering program :)
(but when i'll have finished all the project (tire, wheel and brake) i want to try to create the top assembly on Moi to see how it works :)...I'll try it
:)