JimQPublic

I have an older Thule roof box on a '96 Outback. We have the rear spoiler which wanted to hit the box if the hatch is opened. I mounted the front crossbar as far forward as possible then slid the box forward until it didn't have any interference problem with the open hatch. Then I drilled new front mounting holes in the box; they were about 8" back from the original ones. That put the two cross bars rather close together so I drilled new rear mounting holes as well. It does look a bit odd with the front crossbar almost halfway back on the box but it works fine. I use Thule crossbars. The Subaru bars would probably work if you have U-bolts wide enough to span them. You might need to shim between the bar and the box to account for the arch in the bar. If the box is mounted off-center then it wouldn't be level side to side.

I believe that the Subaru hitches always come with wiring harness and drawbar. Generally aftermarket ones don't. The drawbar will be about $20 and the wiring harness about $35. If you're towing you will need these, but depending on your trailer the Subaru drawbar might not be the right height anyways. If you're getting the hitch for a bike rack you don't need drawbar or wiring.