Painting alone would not cause any change, but if the car was put into an oven for the paint to cure, depending on the temperature, it might. I have seen paint jobs where the entire car was stripped of engine, tyres and interior, all plastic parts and baked at elevated temperatures. It's not very common. The torsion bars serve a dual purpose: They hold the trunk lid up, or hold the soft top lid up. Not both at the same time. There is no scraping against body parts. The torsion bars do get tired; I have seen that they loose the temper. When that happens they can be re-heat treated or replaced. You can try to remove them and wind them up past the elastic limit. If they stay that way, they have not lost their temper.