Because of how they mount IDK if they will work with the lift bars. If you are just drag racing then I wouldnt get them but if you want handling I say YES! Ya know how much better the chasis gets with SFC? Well the panhard gives you just as much if not more improvement. I only had one Fox with one but damn that thing could handle circles around my Cobra it was so well planted in the corners. Get one, I highly reccomend them
I'd highly recommend a Panhard bar if you want the rear end to follow you around the corner in basically the same line as the front end did when it come out of a hard corner under hard acceleration.
I know they are way different chassis... but you can feel the difference with no panhard bar (Fox) and the S197. The rear end comes around SO fast on the Fox and the S197 just doesn't any to come around at all.