Newby Q about impedances etc.

Hi,

I'm a longstanding audiophile-wannabe, but I have very little actual knowledge. 

The system I've used for a long time is a Krell KAV 300i into Dynaudio Contour 1.1s. 
The Krell is fed through a Chord Hugo into a Microzotl2, a tube headphone amp that also doubles as a pre-amp. (Most of my recent listening has been on headphones)

Anyway, the Dynaudios are damaged and I want to replace them. 

I like the sound signature, and I have a small listening space, so I'm considering the Confidence C1s, which have the following impedance profile: 
Sensitivity 85 dB (2,83 V/1 m)
IEC Power Handling 170 W
Impedance 4 Ohms

Or, the KEF Reference 1:
Amplifier requirements 50-200W
Sensitivity (2.83V/ 1m) 85dB
Impedance 8Ω (min. 3.2Ω)

The Krell is kind of old, but it delivers 150W/ch into 8 ohms or 300W into 4 ohms.

Is the Krell powerful enough to power the Dynaudios? It seems like it should be, but I want to make sure. I found reviewers saying that it shouldn't go full-power into 4 ohms for extended period. Of course, my listening isn't going to be at full power, but I want to have headroom as well. 

Finally, I'm going to be auditioning these speakers, but I expect them to sound different in the store than they will at home. Anyone have any experience or comparisons between the two? 

Thanks a lot.