We hired a capsule but to be honest, (if there is a) next time, we'll just go straight to car seat. DD grew out of the capsule too quickly so for us it was a waste of cash!
My friend bought the whole clip is system for her pram but her DS (born 35 weeks gestaion and weighing 2.6kg) was too big for it at 2 months. It was too awkward to carry him in it.

I decided to go straight to car seat and I think the seat is fantastic. Brought DD home from hospital at 2.4kg and not an issue