I've lamented about the lack of places to secure things in the trunk of my '09 WRX sedan. Seriously, there are no compartments, no tie downs, nothing. Here's a quick project that'll cost ten bucks, take just a little bit of time, and will give you as many tie down points in your trunk as you want.
First, I went to Home Depot and bought a few different sizes of rubber plugs and two different sizes of eye bolts. I used 11/16" diameter plugs with #4 hooks in the top of the trunk, and 1/2" plugs with #6 hooks in the side of the trunk.
Next, I drilled a small pilot hole down the center of each of the plugs. You don't want to take much rubber out, so drill the smallest hole practical. A smaller hole means there's more that's left behind to be compressed up against the side of the hole once the eye bolt is screwed in.
Finally, go down to your car, put the rubber stoppers into any hole that you want them in and screw in an eye bolt. I removed the fasteners that hold the carpet to the side of the trunk for a place to put the 1/2" plugs. There are plenty of holes all over that'll accept the 11/16" plugs. When you're screwing the eye bolt in, hold the stopper still to prevent it from rotating in the hole and getting cut up. That's it!
This install could be improved by putting a grommet around the hole to reduce wear on the rubber stopper. The ones I installed seem to hold just fine, but I'll go with a grommet if they start to wear out. Also, there are still no anchor points on the bottom of the trunk. If anyone has any ideas, I'd love to hear.