You could do no wrong with the HSU and they are cheaper too. Check out anything from Craigsub and on AV123 forum he has quite the thread going for his sub comparisons. Some of it has been posted on here, no time for me to search though. Basically the VTF3Mk3 gets more points from him for a deeper extension and its cheaper than the Axiom.

Jason
M80 v2
VP160 v3
QS8 v2
PB13 Ultra
Denon 3808
Samsung 85" Q70