59Burst,
Krell amps work fine with B&Ws but you need a very good preamp, my preference would be a tube preamp. I use the Pass X-250 power amp and I have a BAT VK-30SE and a Pass X-1 preamp to drive B&W matrix 803s. I know that the 803s were not be best speaker B&W made, the 801s & 2s sounded better but it was all I could afford at the time. So far with every change in my system, front end and cables, the speakers have gotten much better, now I am looking for speaker stands. Your speakers will also sound great but I do not know what the rest of your system includes.
The Sim is a great amp also, I also demoed it a few months back along with the Linar Audio amp (from Victor Sima's new company). The Pass was more refined sounding with greater slam and deatils were about equal. They are both good amps. There are a lot of Pass amps for sale used and Pass is a wonderful company to work with. I had issues sending amps to Canada in the past because of the added customs charges. Also the Pass is built like a tank, a real tank. After moving 12 amps in and out of my system, I new the Pass would be playing music for a long time. It was also dead quiet.
If you need a great deal on a Pass amp, let me know and I will get you in touch with some good dealers or jsut want to ask me some more questins, then email me directly.
Peter