Yeah, they're great for drag racing. Not so great for handling, or ride quality.
It cracks me up that people won't run large torsion bars up front because they "ride too stiff", but don't have any problem throwing SS springs on the back. The factory rear spring rates weren't nearly as far off as the fronts, and 160 lb/in springs pretty much guarantees the car is oversprung in the back for anything other than drag racing. Factory XHD's were 110 lb/in, and most autoX and road course springs are around 130 lb/in. And those are intended for wider tires with better tread compounds than what most people run on the street with their 15" rims.