I was looking to get a roof box for extra cargo but decided not to for the price was too high for my budget and I don't need the extra cargo space that often.
When I was researching, the Yakima Whispbar would be my choice. Suppose to be very quiet.
http://www.rei.com/product/835227/wh...-rail-bar-pair
As for the roof box, I would get this Thule 612 Hyper XL
http://www.llbean.com/llb/shop/78004?productId=1291017
I like roof box as opposed to ski rack because the box has protection from outside elements