Per Michael Daly:
Now that someone has done it, perhaps other car manufacturers can provide
a similar system and we can use _one_ roof rack system with lots of
vehicles without major compatibility problems.

I've never tried it, but have heard several times from people who seem to know
that the ultimate retrofit system is those bolt-on gutter-simulators.

I've got a Suburban with the factory rails on it. They've worked so far, but
my suspicion is that the bolt-on gutters would have been just as strong or
stronger and allowed the load tb 3-4" lower down.
--
PeteCresswell