Welcome, woofersus!

The M3s are great all-around speakers. Unless your room is cavernous you should be able to crank up the M3s no problem. For a short while I paired up my M3s with a Hsu VTF3 mkII and liked the results. The STF2 or VTF 1 should work very well for you. Also, you might check out Outlaw subs. The LFM-2 and LFM-1 Compact seem to fit the small size requirement. I have not personally heard these subs, but I believe Dr. Hsu had a hand in the development.

***********
"Nothin' up my sleeve. . ." --Bullwinkle J. Moose