It was, had a hard time justifying it, but after researching the cool tech bar and knowing how much cleaner the x-brace made the whole rear seat delete look....plus my bonus money this year, I had to do it!
Its a bolt in design. I wouldn't say the X-brace itself does much but the way the roll bar incorporates a rear tower brace over the rear shocks and locks all of this in with the rest of the bar may have some stiffening effect. You can look at their page for better installation pictures and the research behind the bar.