For what it's worth. When I set out to replace the base sound system in my 2010 Prius II, one of the requirements was a sub-woofer in the back. Placement had to be such that I could change a tire in the rain with out moving or exposing said unit, amplifier or other related component to the elements. Well coming home today after Christmas with the relatives it happened, and I'm happy to say it was the right thing to do. A 200 mile trip, raining all the way, and my front passenger tire went. Moral of the story...if you put a sub in back...it can and will happen. See gallery for my solution. mgb4tim's enclosure or similar would also be good.
That is very good to know, I get a little bit of graze, against the sub enclosure, as I lift up the deck to get to the spare, but very glad I installed the amp under the driver seat instead of the cubby in the trunk. The grazing is not Tim's fault, I had Texas Audio do the face of the enclosure. They did a great job, it's just a tight squeeze. Biggest problem will be a dead battery, not looking forward to that day....ughhh. Removing the sub is NOT easy (screwed in at two points, inside the enclosure). But, hey, it's not going to come flying out and hit me in the head in an accident!
I am about halfway done with my enclosure and this was one of the main reasons (quick access) for doing it. However I did leave the amp in the tray but I wired a quick disconnect that will make that a non-issue.
I might have to redo the wiring at the box for quick disconnect. It's currently wired direct to subs, with sealant around wires at the hole. Not good when I need to get to battery.