Gladen RS-X 6.5 - single 6.5 sub - RMS power - in my enclosure is deep and windy for what it is

First, sorry for the bad sound quality: my phone's microphone can't keep up with loud deep bass, mainly with bass under like 38-35 Hz, so this is the reason why the video sounds weird mainly at that 20 Hz-ish bass. The audio system + the sub too in real are sounding normally / cleanly, not as in the video.

For making a subwoofer like this I got inspiration from Pure Sesh's subwoofers, mainly his smaller ones which are tuned very low and they are super windy (mainly his Sundown X10 subwoofer). First I've tried to simulate his subwoofers, then I found this Gladen 6.5 inch sub driver which have similar peaky transfer function in my box in car at the very low 20s like his subwoofers + have ideal RMS power handling from 20 Hz upwards which was my need, so this subwoofer is the result. Pure Sesh's channel: https://youtube.com/channel/UC28kUENpWbjVTuRG9ueeR3Q , his Sundown X10 subwoofer: https://youtu.be/8n3RmNQAZZY

Also, This was just a quick test setup, so I've just threw my test bench into the trunk. My test bench is made of an old Sencor head unit + Audio System CO-95.2 amp + 13.8V/40A Graupner power supply. I've not used the Sencor head unit, just the amp and the power supply. I wired / switched the amp in high-level input mode, adjusted the gains, and that's all. Also, my other sub is not wired in this video, just I leaved it there...

Maybe if I've tidy up the stuff in my car's trunk, place the sub normally, wire / mount the amp normally, then maybe it will sound a bit more louder and better...

The box simulation (including my car's cabin gain) / design / build / finishing is made by me, cutting the box parts is made not by me, because I have just very basic tools for cutting wood, so those tools are not enough for the dimensions accuracy I required.

The box have 22.6 liters (0.79-0.8 cuft) net volume, tuned to 22.1 Hz - this is a bit more than twice as big as net volume + tuned to around twice as low as it Gladen recomends for this RS-X 6.5 driver, but it still not bottoms out on it's RMS power - which is 250 Watts actually - (not overpassing Xmax) at 20 Hz and higher, because it have relatively big Xmax for it's size + stiffer spider. The other details are in my shared project and in it's description: https://speakerboxlite.com/project-info/17627/tab-info .

The reason why I've chose this song: 【Extreme Ultra Low Bass Test】ONLY 1% OF PEOPLE CAN PLAY THIS BASS (20Hz) - https://youtu.be/H5Ualgs9dz4 is that because the two main frequencies in it's bassline are 20 Hz and 36 Hz - 20 Hz is almost the theoretical sound-peak in my car, and theoretically at 20 and 36 Hz reaches the driver it's Xmax - I can confirm that in real this fact is almost ideally OK by this theory.

Intro song is from youtube's audio library: Life After Death - DJ Freedem.

Video parts:

0:00 - 3D design
0:12 - Simulations
0:48 - Building the enclosure
2:04 - Test in car: start
2:31 - Test in car: windyness
2:56 - Recording from passenger seat
3:11 - Trunk and stuff rattling in garage
3:26 - Excursion time! :)

Thanks for watching :)