I've transported five bikes at a time all over the country on Yakima roof racks. In my opinion your only concern in regards to the performance of the rack would be with cross bar flex.

Look at the pictures below.

On my trailer I used short towers and did flex the bars enough to dent the roof on the trailer one time. Of course a small pop-up trailer develops some nasty bounce on rough roads, probably much more than a loaded vehicle would. Notice that those are all Mtn. bikes loaded up there on the trailer, definately more than 35# each.



On the Caprice wagon I used high towers to clear the luggage rack.



I believe Yakima produces great roof racks.

I won't address vehicle handling characteristics other than that I never had any issues at all on the large vehicles you see here in these pictures. Don't forget to pack a small step-stool as it's a long ways up there when loading and unloading those bikes in the center of the rack!

I hope this helps to answer your questions.