Roof rack without rails or should I have rails installed?

[raspire]

Got a BMW 2 series F45, planning a campaign trip to Cornwall this summer with dog and family. Car will be full so need a roof rack, the car doesn't have roof rails at present, I could get them installed but it looks quite costly directly from BMW.

I have seen roof rack bars that clip onto the edges of the car instead, just trying to work out the pros and cons of both so I can make a better decision.

If there's not much difference I'll go for cheaper option

[E-bmw]

If you stick with a known make (such as Thule/Mont Blanc/Summit) they should be OK.

I have used Thule on 2 previous bms with good results.

[ninjag]

I would also recommend getting the aerodynamic kind rather than square, looks a lot nicer when the roofbox isn't on.