Falcon, I've had the M22/VP100/QS8/STF-2, and M60/VP150/QS8/VTF-3R in a room about that size.
Both are very good and you'd be happy with either one. If you an afford it (both money and size-wise) the bigger speakers and sub are worth it. It's a definite improvement.
However the smaller configuration is by no means poor. It would probably sound better than anything you've ever heard.
Measure sizes carefully, especially for the center channel. The VP150 is significantly larger and heavier than the VP100.
