I did a good bit of research on sub boxed for the 370 myself. It broke down to 3 options for me.
-Zenclosure: cheapest, look nice, sound good, easy/little work to install, more speaker options: big, take up good bit of trunk, not as custom looking, people can see your stuff through the hatch glass
-Wicked CAS: looks nice, looks custom, sound good, easy to install, dont take up much trunk space, cant see from hatch glass (both corner and spare model): cost a good amount of $$
-build one yourself: how nice and custom it looks depends on your skill, can still cost you good $$, take a long time and planning, requires the most effort, hopefully it will sound good, can or wont take up space depend on design, has the "I made this" coolness
I opted to make my own. I'm fairly handy but this quickly became a big job. I have never worked with fiberglass before. I read and watch online videos on how to work with it and bondo. I should have kurff (sp?) the front edge instead of just t'shirt finberglass it. It would have been faster and less effort. Anyhoo, it turned out nice. Hit hard and solid. I got ideas from lots of online pics. I seach for weeks before I came up with what I wanted.
total cost to make the box in material: ~ $200, fiberglass mat, fiberglass mesh, bondo, mdf, glue, vynle, polyfill, speaker terminal
total time invested in building just the box: about 25 hands on hours. Took some work!!
This is teh view from inside to give you an idea on space for speaker excursion/truck space.
Simple mounting board behind my passenger seat for the amps and wires. I'm in the process of changing a few wires as soon as I decide on a new deck. Stupid phone jack audio is BS!!
YzGyz