I have no experience with Gryphon, but quite a lot with Pass Labs and Krell, currently I use a pair of Pass XA 160.8 with a pair of Wilson Sasha 2, and since I have them I have been wanting to try other brands, for me They are the most musical and dynamic amplifiers I've ever had. I highly recommend them, plus Pass Labs have the best technical and customer service of any brand, something that is very important at these values. that the better it is, the more music they deliver. I gave them the top-of-the-line Furutech Nanoflux plus FLUX 50, with a dedicated current line, with a Furutech GTX DR nano chip. I do not agree with the idea of mixing brands, for me the best synergy is always achieved by respecting the same manufacturer, since they think of the equipment as a unit. I put the Pass pre-stop on the XS and I am in heaven in terms of textures , details, mucicality, definition, and stereo image. Good luck with the choice