Never heard the sp16 but did own the Bel Canto Pre3 as well as a few other ss preamps. IMO the pre3 provides absolute neutrality. The volume goes up and down smoothly with not a hint of coloration no matter the setting.
If separates were in my future, for the money, the pre3 would be the preamp.
If separates were in my future, for the money, the pre3 would be the preamp.