My Kemper goes through my M-audio Interface into my monitors. I have used the Kemper with out the interface before but it makes little difference. when using the Kemper with my studio headphones there is definitely a change in the sound. Its not necessarily a good or a bad change it just sounds different, Maybe a bit more present and clear with my own profiles but with the imported profiles it doesn't really help the tone much.
I tend to always use the boosters when making my own profiles, however with the Imported profiles i still can't get close to what the YouTube demo's sound like.