ditto for me. I was another poster on that thread and returned mine to compusa as well. Lest we start yet another internet myth ("Darla, the SUB KILLER")...

My GUESS is a bad manufacturing run. I called tech support and he knew right away what I was talking about and told me to visit home depot...
If you have the issue, it is visibly (and touch) noticable, as described in some of the posts. You visually see that one or two of the screws don't attach to enough surface area to get a good seal -- they just don't look right compared to the other screws. You feel a strong burst of air in this area during an extended low bass scene like Darla's. Now I ain't no expert but I don't know that a sub is supposed to do that. You hear rattling during this. In hindsight, I recall that it just don't sound right either when doing a frequency sweep and it get's lower (under 40hz or so).
By the way, I did attempt the self-repair and still felt some air. Plus, I got myself further confused after the initial re-assembly when nothing at all could be heard from the sub. After another dis-assemble I found that one of the leads was disconnected. At this point, I just said screw it and returned it.
I since re-sequenced my upgrade strategy and just ordered a new VP150 center. I'll replace the sub later...

Which now leads me to a question suited to this forum... all along I was just looking for a sub that was econimical with good musical detail and accuracy (to fill in my M22 mains). I do watch a lot of movies, but I live in a condo and wasn't really looking to shake the foundations anyway. I succumbed to the buzz and tried the hsu. When I do decide to get the sub again, I may still go with that. But I guess I am more curious now as to what is wrong with the axiom subs and why do many axiomites have the hsu, svs, etc. ???