I used to run them...but my car sees a lot of street duty. They completely ripped apart my torque boxes. I repaired my boxes by following an old article of MM&FF where they use 3 brackets on each torque box to help give it some reinforcement. I added a 4th bracket just to help stiffen things up. I got rid of the SSM lift bars...put the stock lower control arms back on and bought Lakewood traction bars. They work great...and I've actually turned a better 60ft. time (1.67) with the slapper bars.
Even if your car is strictly for the track...you're going to have to beef up those tin cans that Ford calls torque boxes. The metal is ridiculously thin where the lower control arms bolt onto the chassis.