Is the M3 good enough for mains in 14x20 feet room. Gonna have to go with bookshelfs and with WAF can't use floorstanders and on a budget. How much different is m22 from m3 since they have same freq response and I'll be using a sub.

M22's are better speakers...

they have a flatter response and they're more neutral and clear.

either way, with a decent amp, both speakers will play at a decent volume level in your 14 by 20 room, but don't expect them to rock out.

My room is just about that size...maybe a tad bigger. I have the M22ti's and with a good subwoofer, they work really well.

The M22ti is a cleaner, crisper sounding speaker. The M3 sounds a bit deeper in the bass, and a little less crisp in the highs.

Will you have a subwoofer with these? In a room that size, you're really going to want one to fill in the lowend.