Mark, that is awesome that you're trying to fix your room problems. I'm currently running three subs and they do a great job of evening out the response (I've measured with my SPL).
Hmm, I'm thinking if you put the two subs in corners you're not getting the true benefit of multiple subs--they will both reinforce or not play certain frequencies. I had better luck with midwall or thirds on each wall. Easier said than done, though because you have furniture to fit in. And in a small room there is just not that many placement options.
As for which subs to get, hoo boy, that's a tough one. Because it seems to be the new hot item I'd be inclined to try the new Axiom 350.
On the other hand, Hsu and Outlaw are great subs too. I have a Hsu VTF3 mkII in maple and I love it. The maple is a fair tonal match to the Mansfield Beech. I don't have any pictures of my old M40s and Hsu together to give you a comparison. My sub sits out in the open and the lighter color is excellent and seems less obtrusive.
I'd say the low end response between the Hsu and Outlaw is negligible. I believe Mike (mdrew) has an Outlaw sub. You might send him a PM and ask him about it. From what I remember he really likes it.
