Ahh, so there are threaded inserts under the mounting point covers on the roof? Is it easy to take those covers on and off? I'd seriously only be using the rack like 2 or 3 times a year, mostly just when we get relatively lightweight but bulky items from the store (replacement interior doors for the house, flat-packed bookshelves from Ikea, etc).
I installed the rack last night, peice of cake. The little plastic covers on the roof rails are easy to remove. Just get a small flat-head and insert under the end opposite the arrow, push forward a bit and when it drops into a little hole (under the insert) the insert will pop off as you pry up with the screw driver handle.
My rola rack (part# 59714) installed with two bolts (one being a torx style for security and PIA purposes) per corner. One to secure the tower to the car, and one to secure the crossbar to the tower. I think it looks great, and should be able to hold 3-4 kayaks without issue. My only concern is the short crossbar spread is not ideal for longer boats. Also due to the aero-blade crossbar shape, by yakima rack accessories (stackers, multi-mount) will not work. I have universal mount bike racks and a yakima cargo box that should fit fine. I'll get some photos up when I have a chance.