The HW 18" will handle the power you have in the correct box. Here is a vid from today, Two d9's @ 0.35 ohm daily on two HW 15" dual .7's.
They have the new cone and 66mm tall coils they do very well on the lows.
The SHW V.2 is VERY CLOSE to being complete. The V.2 has some benifits over the V.1
First is we have a daily version and a SPL version, the Daily version will be complete first
they are
Stronger cone and surround
Linear coil technology
Spiders a 10" in dia
50% more contact on the Triple joint
over 25mm of xmax on way
80+mm tall 4 inch , 8 layer voice coil
and many other small improvements