Less safe under certain circumstances would be more accurate. There are good reasons for having spring rate choices. In a grocery getter, it probably means very little except for ride comfort. In a drag race car, slalom car, high speed oval car, or, on the street in an emergency situation, it can mean a world of difference. The weight and weight bias is an important factor too. That's why there were several options available from Mopar from day one. Otherwise they would have just had one bar for all applications. Usually, having a stiffer torsion bar (and springs) will give you better cornering and emergency handling, but, you can go overboard there too and actually make it worse if you go to extremes on a light car. Choose a torsion bar (and rear springs, shocks, and sway bars) according to what you intend to do with the car, the ride comfort you want, and the handling performance you hope to achieve.
