I confess to being a slow learner. I have had my Roadster Sport for ten years now and changed the usuals in the suspension dept. Panhard Rod, brake reaction bars, etc but the other day remembered that the shocks were adjustable so stiffened them by two clicks all round and suddenly the car felt factory fresh . I don't know whether a change in the rear suspension would make it any better ( it has never bottomed out ) and I have no experience of the CX chassis but this was a terrific change for free.