Hi there. I haven't taken them to the track yet so not fully sure, but roll is better. I don't push the car to the extreme on the street much. They have 5 settings, allowing adjustment from 7% to 70% stiffer than stock. 1 3/8-inch diameter (front) and 7/8-inch diameter (rear) tube bars. Personally I'd go with the 350evo bars if I was buying new since they're cheaper and can come with the better polyurethane bushings for more.
I'll probably stiffen up the rear to the max for the track and leave the front at the middle setting which should help more with understeer.