I've got a set of Intrax on my GTV they are superb if a little hard for some people's taste. Hydraulic bump stops mean even when low it rides very well. Mostly a magic carpet effect. It's the undulating and rough surfaced B roads it feels a bit hard on.
I've also had FK's and would say by comparison they are an absolute waste of time rebound was harsh dampening poor pretty much a waste of £400 they are however adjustable at the rear although I found the coils tend to be compressed to the point where they are almost touching.
'98 916C1 GTV V6 24V - Rosso 130 - 885 Tan Momo - 321 Wood pack - 17" Tele - Zender 'cup' Aero - BMC CDA - Wizard Quad - ELDP - Over racing Ti strut brace - Intrax RS coil-over