800's absolutely shine with the Burson Soloist. Reaching the Sens full dynamic potential is fully achieved. I know some have said that the treble and sibilance are a bit piercing at times but buying a really great DAC can clean up that problem instantly by smoothing it out with the rich and warm analog sound that of course a DAC carries.
You don't have to go crazy and risk coloring the 800's dynamics in place of a warmer vinyl like sound by opting for a tube amp or cable upgrades. Personally the cable upgrade game is really tricky and people should be very careful with their $$ when looking into those matters. When you already have high end gear in your sound chain AMP+DAC+headphones cables can really only create differences that are very small. Like 5 to 10%.