the 307 and c4 both share the same floorpan, engine and gearboxes, most likely the suspension too. mines a vts and i dont find it too hard unless the road is really crap.i drove a c4 hdi a few weeks back and that felt a bit softer than mine but quite a bit more body roll. try driving a older ford, my brother in law had a fiesta ghia a while ago and it was horrible, the ride was rock hard. so i dont think the c4 is bad at all