Whoa! Slow down. The description of the sound you gave comes from a synergy of AMT drivers with a nice natural amp like a Pass XA30. If you want that sound you are not going to get it from some KEF bookshelf speakers and the quick choice of a high powered amp. Choice of components trying to achieve a particular goal takes a lot of work and patience.
The Pass amp you had is not noisy… period. If it sounded that way then it was probably an upstream component. Also, you are not going to fill a huge room with bookshelf speakers.
I recommend stopping for a while, taking stock of where you are and where you want to go. the Pass XA30 is an exceptional amp. You could consider a XA60. But for speakers you either want substantial sized floor standers with an AMT driver, or Maggie’s, Matin Logan speaker or some othe planar speaker. The latter two will require an amp like a Pass x350.8. But it is not going to be as warm as the XA. I chased this dream for nearly 30 years. If you have a $100K to drop, it is pretty easy to solve… I assume you don’t.
I am happy to help, but recognize an amp purchase is not going to get you where you want to go. You need a strategy… and honestly your current strategy is going in multiple directions. If you want to talk off line give me a holler. You can see my current systems by clicking on my ID.