So we're thinking about getting roof bars and a roof box for weekends visiting family etc. (rather than buying a bigger car) - but I haven't a clue how they work and can't seem to find much information. Can anyone who has them tell me if you can take the bars off easily when not needed (for sake of fuel consumption, wind noise etc.), and how much of a faff this is? And are roof boxes safe, like for driving on a motorway when it's windy...? Thanks!