I would say it depends. I had a Chevy S10 blazer and just used the factory cross bars. After one summer of hauling boats the entire rack started to detach from the roof. I had to remove the trim from the inside to access the attachment points and tighten them back down. It was a big hassle and I always worried about the boats flying off after that.
Now I have a different S10 with Yakima cleats and crossbars, haven't had any problems, just finished my second season with it.
You ARE a soul, you HAVE a body.