I would looking into the Thule system it cheaper and better then ...I have carry a kayaks and my mountain bike.....
Thule Car Racks - 2009 Thule 400XT Aero Complete Car Roof Racks
Thule Kayak Racks & Canoe Racks - Car Roof Carriers
as for ground clearance it can't go through any area made for 4X4 or need of high ground clearance like 36" but I usually take my fit out to the back country of the Sierra Nevada In California a lot....