If you mean one like the 5.0 Mustang guys use, you are SOL. The K member is an integral part of the frame and removable only with a cutting torch! If you like welding, get a street rod style Mustang II front suspension and fabricate it yourself. Remember that a G body is a body on frame vehicle, not a unibody like a Fox body Ford or an old Mopar. Besides, unless it is a pure drag car, it is not worth the expense as the gains would be minimal for the amount of headache. What is the intended application anyways?
As for the one posted, it would be heavier than using the stock bracing because it is made of a sturdier material. However, I like it and want one for my car!