HSU Research has Labor Day Sale for 2 lowest model subwoofers.
VTF-2 MK5 $509+$65 S&H=$574
VTF-1 MK3 $379+$54 S&H=$433
They also have HB-1 MK2 bookshelf speaker for $139+$29 S&H=$168
I was planning to get 2x VTF-2 MK5 so this is great timing. Not a deep discount but these rarely go on sale anyway.