Spring and damper rates are the same as the ST24, but the wishbones and bushes are as per the ST200. TBH most Cougars which haven't had new dampers by now will be driving fairly poorly, and as the anti-roll bars weren't that thick to begin with, a decade's worth of corrossion will have thinned them a lot. In addition, anti-roll bar bushes tire out and most people only change them when they're so dangerous as to fail an MOT.
My advice would be to:
Renew anti-roll bar bushes
Renew dampers
Renew anti-roll bars themselves (along with droplinks)
Renew front wishbones
Renew rear control blade bushes (think that means new blades - but I'm out of touch these days)
Renew springs
In that order. It'll drive as tight as a drum (or at least as well as it did new) and you should get a nice improvement each step along the way. HTH