Basically any sort of cover for vehicles such as mesh or canvas roofs should be allowed to move around to show the lovely physics influence on the object. Spin Tires, Mud runner or Snow Runner series had a try at giving the material covers for cars physics so they move around but it looks a bit off...Still a good idea tho.
The entire thing is laggy, so I don't think the tarp influences it in any way. On our B1 we have softtop roofs which have physics to them & flap in the wind a little but I have yet to notice a different in fps between having that roof equipped or not
For me removing the BigRig tarp massively improves the FPS, the complexity of it is comparable to the CH dummy judging by the lag
