I own a Vandersteen 2W sub, which i pariedwith my norh marble 9's for a while.
It has since been replaced bya Bag End Infrasub-18, which thoroughly destroys it in terms of tonality and musicality.
The Bag is better, deeper, more musical, and stronger.
Likethe Vandy & REL, it is a music-first sub, and NOT for bone crunching SPL's for HT-
I would recommend getting a musical sub like the Vandy (or you can see I preferthe Bag End), then a second for the HT explosions if you need that.
dg