Hi Guys, I want to know is it possible to replace ingame cars with Addons cars?

I opened files from an Addon Car with OpenIV and extract ytd files, that worked. But the car has mod parts when I use it as Addon but not when I using it as replace. So I need to extract the mod files too. I found them done it but the tuning does not appear ingame in the tuning garage and gauges on the car does not work too.

What when I try another approach on this. I install the car as Addon, lets say Audi RS7, but want it to replaces Obey Tailgater, which text file I need to change, that the game read the Addon car instead of Tailgter?

I hope someone can help. I want to replace all cars with nice cars and tuning options in workshop.