I bought my Axiom system last Chrsitmas and your post reminds me of the recent choices I had to make. I am really happy with the results so here is my input:
1- I based my purchase on the EPIC60 system but with some changes. For me, clarity of the dialogues and frontstage was more important than earthshaking bass, so I upgraded the center to a VP150 and downgraded the sub to a EP175 (couldn't afford both). I am really pleased with the results. The bass is not extremely strong but it is tight and blend very well with the M60's. If I want to upgrade later, I can always add a second EP175. From what I've heard, it will also be easier to reduce the effect of standing waves using 2 subwoofers anyway for a better distribution.
2- I have no doubt that the QS4 are great speakers but I went with the QS8 just because the tweeters are the sames than the rest of the system and from my research, it is always a good idea to go that way in order to have a matched"timber" across your system for a better blending. Dimensions of your room also suggest that you would could use the QS8. However, if money is tight, I'd go with the QS4.
Hope this helps!
