JS-9411 - XJ Frame Strengthener Kit SKU JS-9411 $349.95 Quantity discounts available QuantityPrice Quantity -+ Add to Cart Details Frame strengthener kit for XJ Cherokee vehicles. Basically a subframe connector kit that substantially stiffens the unibody vehicles. Weld-on. Details Back DetailsFrame strengthener kit for XJ Cherokee vehicles. Basically a subframe connector kit that substantially stiffens the unibody vehicles. Weld-on.