Adding new modules is easy. Just slip the module into the track in the load bar and you are set. The only tool necessary is used to attach custom clips to the feet. We had this rack setup with all of the modules in less than half the time it took to install the other racks. Only one measurement is required to get this baby hooked up and ready to go.
Pressure is applied to the feet towards the center of the car while adjusting the tension.
This resulted in slight dent damage on my roof beneath the rack feet. Because the trays don't have end caps I lost a strap that worked its way off an unloaded tray and onto the highway. The Yakima rack is built with stainless steel clips that are thinner than other racks' clips. Thinner clips enable a good grip on tight fitting doors. The crossbars are round to give you control over module adjustment.