Car-back = limited utility to me
Oh, I see where the luggage rack comes into play. Gotta have it for the car-back to hang from.
I can't get too excited about a car-back simply due to worries over how badly the car's finish would get scratched up. The model linked also shows fairly limited dimensions and a carrying capacity of 100 lbs. That's the equivalent of 2 airline-ready checked bags.
The 1.25" receiver hitch, on the other hand, would probably be rated for 350 lbs tongue weight of a trailer, so it would also be able to carry a little < 350 lbs of gear, where the weight of the rack itself must be taken into account. I don't know if receiver hitches are rated down as low as 2,000 lbs towed weight, but if they are, and if only a 2,000 capacity can be installed on the Mazda 9, that still gives you a shade under 200 lbs of cargo weight, where hitch standards normally rate the tongue weight as 10% of the towed weight.
As noted, we find the receiver hitch to be very useful for bike racks and ski racks, as well as a variety of light trailers.
Foy
