Installation:
!!!For install you need Assets Bundle Extractor which one can be downloaded here https://7daystodie.com/forums/showthread.php?22675-Unity-Assets-Bundle-Extractor and unzipped my file!!!
1.Make copy of your files!!!! Then , Turn on Assets Bundle Extractor
2.Click File--->Open
3.Look for file named "sharedassets3.assets" in ***\steam\steamapps\common\My Summer Car\mysummercar_data\***
4.Click at it and then click open.
5.Click view ----> Search by name
6.Type here furdice and click search
7.You will find material, so click F3. If you find a Mesh. This is the file.
8.Highlight it and click "Import Raw" on the right side.
9.Find my file and import it. Then click file----> Save and save it with "sharedassets3.assets" name in another folder of my summer car. Then copy it and paste it to the mysummercar_data folder.
10. Enjoy