I had an old top for my 914. I bought a set of 4 Yak 'rail riders' and 2 Yak bars. The rail riders bolt through the roof using large fender washers on the inside of the car. The system works nicley to carry my kayak and paddle. I have tested the system to 85 MPH
. Note: I have a bow and stern line attached to the boat that is not shown in the picture below: