I've got a 2010 mini clubman and interested in buying a used thule evolution. the attachment hardware was confusing to me and the seller couldn't help because she had Sears do the installation for her. I just want to make sure this particular thule is compatible with my factory installed roof rack that runs parallel to the side of the car. The thule hardware is not adjustable...

 

You will need some kind of cross bars to attach the cargo box onto. Does the deal include those? If the other car is a Clubman with the factory rails, and the cargo box includes the cross bars, then you should be fine.

Any pictures of the equipment being purchased?

 

MINI branded cross bars have identical dimensions as the Thule crossbars...might be manufactured by Thule....they look like it. I've used several Thule mounts on my MINI R55 cross bars (with the roof rails like yours) with no issues.