Schiit Freya + tube rolling

I’m really enjoying my freya+, I’d like to get into tube rolling. It comes with 6sN7 but I believe it can host a variety of others. Is anyone having sexy results with aftermarket tubes?
Bluesound node 2i > Gungnir MULTIBIT> Freya+ > Accuphase p-250 amp> ascend acoustic Sierra2ex