I love mine. Was one of the best upgrades I ever did. Well worth the money as everyone has said.
But remember every car is different. My car handled like a barge when I bought it. 100k on it and everything was worn out. I put boxed stock lowers on it with AutoZone rubber bushings and a ATR replica swaybar. The big solid one that bolts in the stock location. That and a SC&C front frame brace and new swaybar bushings and shocks too helped the car immensely. Also did the rear seat braces too. Plus I have 16" GTAs with good tires on the car as well.
But getting back the H&R bar, it has to be properly setup. We set mine up with the car level on a four post lift and the tires properly inflated. Been working great ever since. And since it lets the car leave level, it hooks better at the track. My old bar would leave with a lean off the line. No more.
My GN has been 1.54 in the 60' spinning the slicks. So it works. I also run no pressure in my airbags, but they are still intact and in place and functional. My buddies T Type went 1.45 with a H&R bar on a 4psi footbrake launch.
Food for thought here.