Right now I have a pair of M3s as my mains with an Athena centre channel. I've read that you should have all the same make of speaker for your fronts and centre. Could I use another M3 for a centre? Would I notice a huge difference with an Axiom centre over a M3? I'm looking for the most cost effective solution.

The virtues of using a matching, vertical center to your mains are well documented. Such things as matching the power handling to your mains, tonal/timbre characteristics as well as possible advantages in off-axis response over the horizontal counterparts. If you have the ability to place the M3 in its natural vertical orientation then this would not only be desirable but the most cost-effective solution as well.

Cheers!

Unfortunately placing it vertically is not an option,makes sense though. With the space I have in my stand it looks as though I'll be limited to using a center channel

and there is nothing wrong with that.

Racer, the word "huge" almost never applies in comparing quality audio equipment, but a vertical M3 should be better than your present center speaker. Placing it should be possible if you don't insist on using the stand. For example, placement on the floor and tilted upward toward ear level works well.

That would look silly with my setup.It's all moot now though,I just pulled the trigger on a VP100 center.

I can compare my vp150 vs my M3 as center channel and the only thing i can tell you is the vp150 is a way better center. As for the vp100, i guess not.

Someday I'll be able to comment on the difference between a VP150 and a in/on-wall VP100, since I plan on replacing it with the VP150. But given all of the mini-catastrophes that has taken place in my life the past several months, it's taking me a while to financially get caught up. Just this past 2 weeks, a storm has caused me to schedule getting a 400 sq ft room tiled (removed wet carpet), but before that I'm going to replace all of the walls green sheet rock or some light colored paneling instead of the dark color that's currently there.

There. Have I derailed this thread good enough yet?