Found JT's Strong Arms on Amazon with Amazon Prime ... beats the local store price, because the store didn't have the 5th wheel over 58" kit in stock. Then found a new non-prime vendor on Amazon ...
If you have a tall, heavy 5th wheel/trailer then they are definitely worth it. They take almost all of the movement. I suppose you could take them off, it would be a matter of unbolting them. I wouldn't think it would be too big of a chore.