Traction bars

I am looking at getting some traction bars and wondered who makes em I have seen L&L and Fabtech but wanted to get the single bar like alot of guys pulling are using. I think my rearend is moving around on me. Sometimes it pulls hard when i brake when it does this just driving down the road also makes the steering wheel cocked to one side. I rebuilt the calipers put on new pads and rotors and am not sure what else to do. It just feels like the rearend is cocking to one side. Any ideas and places to buy would be greatly appreciated. Thanks Kevin