Levinson or Krell

The 33H would probably be more on the "musical" side while a bigger Krell more on the analytical. I state this with reservations as I have heard your speakers with Krell 600 & A-R, side by side. The ML I heard with other speakers, so I'm extrapolating. Also pls note, I judge by classical music. Your gear is in the big league though! Cheers.

I have'nt heard the Krell 350's but as a general rule Krell's don't seem to be as musical and can be fatiguing over time. However these differences are small and may not bother your ears.
Also try out the Proceed which is a cheaper version of Levinson and is also very good.

I'm happy driving my W/P 6's with Pass X600 monoblocks. The Pass's have pure, smooth, liquid midrange and treble ranges and are OK if not great in the bass. This is a good fit with the W/P 6 which tends to be a little hot and very revealing in the midrange and treble. I don't think they need a lot of help in the bass, so the Pass's are fine. The X600s put out more power than I need for the relatively efficient W/P 6's, so maybe a smaller Pass would be more appropriate. I listened to the Levinsons and thought they were a little veiled or laid back. The Krells sounded a little colored, especially in the bass regions, amazingly for a product at this price level.