So i have been contemplating changing the woofer out on my ED a7s-450 with the LT 1300 amp, the internal volume is about 4.9 ft 3 after subtracting the amp. the SI 18 D2 is around 200$ shipped now through the pre-order and ufokillerz is sellng his Aurasound NS-18 local to me for 400$. i haven't seen too many measurements for the Aurasound NS-18. Is the Aurasound NS-18 twice the value of the SI 18 D2? i mean for 500 i could get 2 SI 18 D4 and one of erich's flat pack and run both off the LT1300 from the ED a7s-450 enclosure, just running wires out to the other box. or i could just get the 1 SI 18D2. Any info is appreciated.