subwoofer small and light horn / reflex?

I need a sub powerful yet compact, to use with a very powerful head (1500w 15 "+ 1" sensitivity 100db) with techno music, house reggae etc.

I can do a sub from 118 liters, I could get to 150, but then it all starts to become heavy to be transported by a single person
I want to use the new iNuke, 6000 or 3000 bridged with 2000w power measured at 4 and 8 ohms ..

I honestly do not know if the aim is better a small horn (cube type) or a reflex like this:
wizardaudio.hu/hasznos/hangfal%20tervek/...ound%20Kit18%20B.pdf
although it remains very cumbersome ..
or 15 ", which from 35Hz up no big differences .. and the box is much smaller:
www.bcspeakers.com/media/W1siZiIsIjIwMTM...vNTc4L2ZpbGUiXV0.pdf

or load a new woofer 18 nd in the box to 118lt .. what do you recommend?
The speakers at the high-performance neodymium That can Keep 2000w amplifier as 18 18NLW4000 sound, 18NLW9601; B & C 18NBX100, 18SW100, 18SW115; Faital 18xl1600 / 1800; 18HP1060

They ALL "vas" 180 / 190dm3
There is also a good rcf LF18N405 but as vas has 227 lt ..
Now I do not know if I should just base myself on that parameter or must also take account of other factors

It has already, a subwoofer Montarbo 119SA, the inner box is only 108 liters, and the sound is good .. but given their small power 600w is not enough!
This volume is partly occupied by the woofer, amplifier class AB, and by reflex tubes ..
I simulated the parameters for the b & c of the Montarbo, with measures of reflex, according winisd only accorded 56,69hz can .. ??? it seems absurd ..

here parameters woofer b & c of the 119SA:
oi68.tinypic.com/j9y90l.jpg

Thanks for your suggestions!