Spectral designs are ultra-wide bandwidth and really optimized when used in a system wide approach with their matched electronics and recommended cabling. It's more than an attempt to sell more of their gear, but with the instrumentation grade circuitry involved the networked cables are pretty much a requirement for their electronics to perform as they were designed and maintain stability. You will hear some reports of users who match a piece of Spectral gear with other brands but that's not the way to get them to perform at their peak level.
D’Agostino amp with Spectral preamp
Is trying to run a D’Agostino amp with a Spectral totally not doable? The reason I ask is that I was thinking of adding the amp in my system first then getting the Dag preamp or a tube pre later. Later is much later like a year. Do you think this would sound terrible?