Just bought an 18 outback base model. I am looking for options on a sturdy roof rack for mounting my spare outside. It's important that I keep the height low as I occasionally use parking garages with 6'8" clearance.
I use a Yakima LoadWarrior basket with an extension, mounted on Yakima LandingPads. The weird thing I did to lower the basket height was to flip over the mounting hardware of the LoadWarrior so that the bars run through the basket instead of underneath it. This drops the height at least 2 inches (EDIT: make that more like 4 inches) and make the whole thing incredibly secure. Now, it also takes away some of the usability of the empty basket with the bars running through it, but the bars actually straddle the spare in a way that makes it even more secure and I always keep my spare in it anyway. What I'm left with is usable storage space in front of and behind the spare where I strap down camping chairs, duffles of dirty riding clothes, and things of that nature.