There are 5 torx screws underneath, 4 in each wheels well and 4 10mm bolts that are recessed *way* inside the rear luggage compartment.

Here are the tools I used:
Torx T-25 bit
1/4" Screwdriver
1/4 to 3/8" drive adapter
10mm deep socket
1/4" ratchet
mechanical claw pick-up




The first thing you do is to remove the 4 deeply recessed 10mm bolts from inside the trunk. You'll need to use a deep socket and you'll want to be very care not to drop the bolts into the bumper space. I removed the tool kit other extraneous stuff from the trunk to make room and used a head-mounted flashlight for lighting. I used a mechanical claw pick up here to actually pull bolts off of the screws since I didn't want to risk them falling into the car.

Here's a picture to show you the opening where 2 of the 4 10mm bolts you need to remove are. There is another opening on the opposite side of the trunk.







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Next, you need to remove the 4 Torx bolts inside each of the rear wheel housings. I used the 1/4" rachet connected to the Torx T-25 bit due to tight space (you could also take off the rear wheel to make space too). The top most bolt is hidden on the opposite side of the wheel liner.








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The last 5 Torx screws you need to remove are located underneath the bumper itself:







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Once you get all of these screws and bolts removed, the bumper unhooks from the wheel housing (looking at the picture above, there's a plastic catch between the middle two Torx screws). Be aware that the electrical connections come out of the car on the right hand side so don't just yank it off. That said, there is a fair amount of slack in the cable though, so you don't have to be overly careful.


Hope this helps!