These racks do exactly what they are meant to do! Still, they are MUCH too powerful for an old Porsche 944, they PUSH the glass out of the top of the car's frame. I should have done more research, what you need to do is place a floor scale between the hatch and hull, find the weight and buy racks for that weight. No need to open the sunroof by yourself, you will regret it! It just needs to be held.