I've got the mopar bars and had the Thule roof basket on top of my WK2 and had loaded with tent, eskies and chainsaw in a timber box. Was possibly just pushing the 68kg load limit, but found having the roof basket attached to front and back rails seemed to strengthen the whole unit up nicely.
I would be happy to put a spare wheel on top except I'd struggle to lift it up or down these days
I definitely wouldn't load anything on top that could be impacted by wind force. i.e. Canoe etc a definite no
Sent from my iPad using Tapatalk HD