Hi, my experience is with Thule and they offer a quality and well thought out products, though you do pay for the privilege. You'll need to get the foot pack (if your zafira has roof rails) and the bars - not much choice on the foot packs, there are plenty for the bars- either square, aero wing shaped bars, or if you value ease of loading sliding bars so that you can load bikes closer to your own centre of gravity when standing next to the car. Also worth considering is security aspects - the Thule products I use are all tool-less to to assemble/dissemble as well as secured with lock and key, so I know it'll be there when I leave it attached to the car. Depending on the bar length and bike sizes you can fit 4 591s, if you have two small bikes maybe best to get 2 591s and 2 532s (equivalent).