DizzleDizzle

That's what I did with my last enclosure I bought the thin walled pvc and appropriate sized end cap plug the rubber kind with the bolt to tighten. I then extended the hardware with a long carriage bolt used the plug with extended bolt to mount the PVC to a drill then I spun the PVC while heating the end and got perfect flares. I also used PVC piece that had the bell end that slide overtop of another piece to make a joint. So I could then flare both ends separately and still fit the PVC into the enclosure cutouts once flared, before pairing them up. Then it's up to you if you want to glue the PVC together to make it permanent or just use some tape to make it adjustable and tunable.

Cool build. Just curious what are the plans for back seat area just amps or do you have other plans?

I haven't heard anything bad about them myself. I have ran the version 1 jp23. I was very happy with the amp. The only problem being it would overheat on hot days. The new line of amps sold at d4s have the internal fan wired to stay on constantly with amp so they run cooler and don't have the overheating problem. I have heard of problems with the Bluetooth bass knobs included with the new line of amps. I guess some have problems with them eventually going out or no longer connecting to the amp. I have seen some people switch it out for a universal bass knob. This kinda sucks to me the clip indicator light was my favorite feature on these. I listen to a lot of different sourced music some of it being rebassed and I could actively monitor and adjust accordingly with the clip indicator. This is the only thing that is currently keeping me from buying the new line of amps.

I am also curious. I found that my deck distorts at different levels depending on what track I play. I dont have a DD1 but I can hear obvious distortion at different levels when playing different test tones.