Looking as some different manufacturers “tough resin” heat deflection temps. They can vary from 120-160 degrees. I would leave them in your car on a hot day for a bit to test before you fully commit to the install
It was in my truck two days ago when it was over 95º outside. It was in an open box and I put it behind the seat so it was shaded but it was still pretty warm in the cab and it didn't warp. Maybe not a perfect test but I think it will be OK.