Speaker and amp compatibility

These speakers are rated at 92db sensitivity. You should be more than fine.

The speakers handle at most 200W, and the amplifier will put out 200W before distorting heavily/reaching its limits, but you're unlikely to actually listen at levels that need 200W. The KEF 104/2 has a sensitivity of 92dB @ 2m @ 2.83V.

Assuming the Sphinx V2 has enough drive (the speakers are 4 ohms nominal, which means they may dip lower, and they may also have some difficult phase+impedance points), you'll probably only use a few dozen watts at the most unless you are sitting very far away or are trying to damage your hearing.

Thanks guys. I dont think I have ever listened to my Rogue above half. 

One quick note - don't judge the power you are using by the position of the volume control.  The knob position does not correlate directly with output power.  At the hallway point, it could be putting out 50 watts,  watts, 100 watts, 28.7 watts, etc.  Many amps have high input sensitivities, so they go really loud early in the volume control range.  It makes you think you've got a really powerful amp, but you can run into clipping before you get anywhere near the top fo the volume knob rotation.