I have the SCA high-lift with Thule bars and various combinations of sit-on-tops on that, usually with total weight over that 35kg . The thule bars are not the prettiest, but they are solid and easy to get additonal options for. I was told that genuine vw bars don't fit the channels in the SCA roof as well. Let me know if you want pictures, although they'd make those who spend half the weekend cleaning their van cringe !