Yes, retrofit kits available - however the AUS RS2k used the rear sway bar as tramp bar/radius rod/track rod.
MANY here will say tramp bars lock up the suspension and are the devils work and that the genuine rear sway bar is poison and should be removed.
In my experience with street driven MK2's I have found that at 14mm the bar has minimal impact on controlling body roll, but is effective in performing a tramp bar/raduis rod function. The key to making the genuine swaybar work effectively is the correct set up of length from diff mount to chassis mount - numbers by the genuine ford manual have been the most effective, the do provide a level of preload on the rubber bushes. If using poly bushes I like to add 5-10mm to allow for less compression and maintain orgiginal levels of preload tension.
Of note in the FIA 5566 homogolation papers the AUS rear sway bar is identified as "sway bar/radius rod" so the intent of the Ford engineering is quite clear.....