Don't see anything wowish here to make such bold statement...Chris mentioned in other thread:
DB15 is said (by a trusted dealer friend, not the distributor) to be 'one of the best subs i've heard'
DB15 is 445 x 425 x 488 (HxWxD mm), 500w RMS and 1000w Peak, down to 23Hz +/- 3db.
RRP will be around £1490
DB13 is 370 x 350 x 388 (HxWxD mm), 350w RMS and 850w Peak, down to 26Hz +/- 3dB.
RRP will be around £1200