I have left modding Spintires and Mudrunner permanently. If I do continue later in life they will be private/friends only.
This is "grass long" just replaced the .dds, and thanks. Need to be darker to match the grass in the pic but for a test it went well.
I opened the image, Magic Wand selected the outside region and in between to make it transparent on the background, tidied it up, saved as DTX5 and voila.
As for movement they move in the exact same way the other grass does.