I would not go to that dealer. The yakima rack mounts directly to the factory crossbars using mighty mounts. Heres an excerpt from their site
www.yakima.com. This is what it says about the X
Warriors install directly to factory rack
After extensive research and testing, your vehicles factory rack has been approved to safely and securely carry our MegaWarrior and/or LoadWarrior System directly on your factory rack. Do not exceed your vehicles rack weight limit.
Copyright © 1998 Yakima Products
Do some research online at their site, and call them if you have specific questions, they are great to work with. Dont let the dealer sell you crap you dont need.... The only way you need the lowrider clamps and bars is if you have no rack crossmembers...
Heres a quick pic