wilson watt puppy 7 and krell 400cx...which preamp

Hi, I was hoping to get advice for a key piece of equipment for my system. I recently acquired the wilson watt puppy 7 and am getting a krell 400cx. I now need a preamp to go with the krell.

I am considering:

1. Krell KCT (so as to employ the cast system). I have heard the cast system is good but have also heard that krell is not known for their preamps?

2. BAT VK50SE.....I thought perhaps a tube preamp may go nicely with the super solid state krell amp.

3. VTL???

4. Audio Research????

thanks

Michael

p.s. My setup is wooden floors and high ceilings.....
primarily listen to rock(radiohead0; jazz (miles davis); and electronica (all kinds).