I have the Saris Bones 3 bike rack for use on my Insight. It works great. The feet are totally adjustable which makes them work well on the Insight. I agree that the bumper needs some internal support. It might be fine without the internal support (mine was). But if it will be getting a lot of use, I think the internal support would be a good idea because the bumper gives a little with the weight. As with most bike racks, access to the rear is limited. But the rack is easy to take off and on once you get used to it, so that really isn't too big of an issue. Check out their website.
http://www.saris.com/products/bones3.htm#
http://www.saris.com/products/bones3.htm#
