We also had the Cloud Z2 and we went for the Cybex Sirona T as that fits onto the Cybex 360 base. My LB seems really comfortable in it.
The base is only compatible with some cybex models and no other brands. We decided not to go for the sirona as it's not much bigger than the cloudz2. We bought a besafe beyond
What centiles is baby? What kind of car do you have? I'd get something like axkid minikid or aviounaut as it's long lasting.