Decided to put it up on here first, since the mounting brackets are already lined up with holes on the upper trunk support (so the sub doesn't slide around).

It has a Polk audio 12" sub, and using the right holes, the sub box sits right in the middle of the trunk. Yes, it blocks the pass through.

The sub works fine and was being driven by a 300w amp. This was in my GF's 04 2.5RS, but the holes are probably the same on all 02-07 WRX/RS sedans. Don't know about the wagons.

$20 picked up in Rocklin, otherwise it goes on Craigslist in a few days.

Reply here if you're interested, I'll get back asap.