If the EP175 pushes your budget I wouldn't hesitate to look elsewhere for your subsonic needs. While the quality of Axiom subwoofers is top notch, they are pricey IMO for what you get. The rest of Axiom's speaker line up are a steal if you ask me. But not their subwoofers, you can find subs that put out more bass for less money if it's an issue for you.
If you're like me thought and are looking to keep the same name on your entire set-up, then by all means test drive the EP175 and see what you think. It might just be all you need. Oh and I can't wait to hear your impressions of the on-wall M22's (or M3's, whatever you decide on) compared to your current Polk's. I could be wrong, but I think you're going to find a big improvement. Perhaps not right out of the box, give your ears a good week or two to really get used to the clean playback of the Axiom speakers. They don't color music like a lot of other speakers do, so they can sound a bit different if you're used to a speaker that does color music. But once you've listened to them for a while and gotten used to hearing music the way it was intended to be heard you will be hooked.
I came off a pair of Cerwin Vega's that at the time I thought were pretty decent. They were lost in a fire, and I went a while without anything at all while I hunted for my new set-up. Once I got these babies (I have the M80's, which have been compared to the M22's only with more bass) in my living room the music coming out of them is so clean, crisp, and detailed... I hear so much more with these speakers than I ever did with my Cerwin Vega's. Every sound recorded, no matter how faint it may have been, is revealed in the recording with these speakers. It gives so much more space and depth to the performance, IMO.
Like I said, it may take you a little while to really appreciate them (it didn't me, I was blown away from the second I hooked them up... but I've heard some on here say that at first they weren't so sure if they liked them or not until they'd listened for a while), just remember you have 30 days to decide. So by all means hook them up, and play them as much as you can in those 30 days. Make sure you think the 175 will do the job if that happens to be the subwoofer you get. Give them a good work out. I know you said you don't like to turn the volume up very often, but put on a live Rush CD and listen to it at reference levels, like you were at a concert. I think you'll be floored by how well they sound. You just might never need to go to another Rush concert again!
....... I'm kidding. I LOVE listening to Dave Matthews on my Axioms, still I will NEVER stop going to see him in concert. His performances are just too incredible to miss.
