its selectable in store you need to choose rolland or itrunner to work proper they are different sizes and need to choose between unload to ground or unload to trailer as for optimazation I didnt make the truck just stretched it and added hooklift and colors and stuff like that Their will be a new version of the truck coming soon its being re done by HAM. I just modify stuff I dont make anything. I know the truck has warnings about the steps being too detailed so maybe that is hurting your fps I run my graphics at twice the max you can go in game by modifying the game files and I only have a 3080ti seems ok for me but my fps isnt normaly great bacause i run the settings at double the max run shaders and have like 800 mods