We haven't encountered any problems with mods from previous versions. 
Greetings!

It would certainly be great to be able to play SD on devices with that operating system, but we do not have enough developers and knowledge to  make this task at this time. Hopefully, this will be possible in the future.

Si tienes problemas con la instalación lo mejor es que pidas ayuda en en nuestras salas de Matrix:
https://matrix.to/#/#speed-dreams-space:tedomum.net

Which version are you using, the latest one? What is your operating system?

At the moment it is not possible to do it from our new official repositories because it is unverified licensed content, but you can do it ‘by hand’ by downloading from the old repository and putting them inside the ‘cars/models’ folder in the settings folder (in ‘/home/[username]/.speed-dreams-2’ on Linux, or in ‘C:\Users username]\Documents\speed-dreams-2.settings’ on windows):

Take a look on this links:
speed-dreams-src-hq-cars-and-tracks-2.3.0-r8786.tar.xz

speed-dreams-src-more-hq-cars-and-tracks-2.3.0-r8786.tar.xz

speed-dreams-src-wip-cars-and-tracks-2.3.0-r8786.tar.xz

Translation into multiple languages is something that has always been on our wish list. The problem is that the structure of the game doesn't make it easy. We are also quite short on developers and time, but we appreciate your suggestion and will take it into account.

It is a false positive from the antivirus, you can rest assured that it will not harm your PC.

Hello, in which version did you find the bug? In 2.3.0 or Experimental? In what OS?

I seem to remember that a couple of months ago a similar bug was fixed, so the next version we release should be fixed.

Use custom livery skins on Speed Dreams is very easy. You only have to put it on the car folder with png format in:
.....\data\cars\models\

Ohhh I think I'm going to blush. Thanks a lot!

For us, Deckard is a General Motors car, as you can see on our Naming Rules:
https://sourceforge.net/p/speed-dreams/wiki/NamingRules/
We don't know if this is what you mean.

What cool cars! Great job!
Please show us more models

Speed Dreams is an Free Open Source Motorsport Simulator featuring high-quality 3D graphics and an accurate physics engine. Initially forked from TORCS, it has now reached a clearly higher realism level in visual and physics simulation, thanks to its active development team and growing community. It mainly aims to implement exciting new features, cars, tracks and AI opponents to make a more enjoyable game for the player, while constantly pushing forward visual and physics realism. It is also intended for any research, study or teaching activity, around physics and AI, thanks to its GPL V2+ license, and the clear and modular architecture of its C/C++ code base.
https://speed-dreams.itch.io/speed-dreams