That's what I did with the front mount on mine. On the seats, I added 2 extra crossbars to the frame, and bolted the seats to those, along with a 1/8" plate about 3"x3" on the inside. If you do anything that may produce a violent roll, you want the cage, seats, and seat belts tied to the frame. You can tie the seats and belts to the cage if it's tied to the frame. My CJ is a rockcrawler, so everything is tied to the frame. It's survived one easy upside down roll with only scratches to the paint, and a broken windshield and windshield frame.

Bob
tufcj