When mounting this rack to vehicles with factory crossbars attached to factory siderails, the low clearance of the crossbars can sometimes interfere with the bindings on the skis/snowboards when sliding out the rack.  Specifically, the lower pair of skis will hit the siderail. Adding a Thule base rack system will eliminate this problem by raising the height of the crossbar.
The Universal Pull Top 6 works on almost all applications because the mounting hardware is universal and can attach to any type of crossbar system with the exception some oversized crossbars like the Nissan Xterra, Nissan Pathfinder, and Hummer H2 have. In these cases you will need to purchase the Thule XAdapt 7, which will include bolts that are long enough to enable the Universal Mounting Hardware to attach to the larger size crossbars.