Ideas for augmenting a Plinius/Lipinski system?

Here's my system: Lipinski 505 monitors, Plinius 8200 mark2 integrated, Thorens 145II turtable, vintage Sherwood tube tuner, and a Sony scd-5400es Cd player (just added). I am considering adding a tube preamp or tube amp to my Plinius integrated (has pre-out etc.) Perhaps a used CJ, pv-12 or 14 peamp, or mv-60 or Premier 11a would be in my budget. Not sure which arrangement would be a little more forgiving (the very revealing Sony 5400 has really made this an issue), and yet retain some of the wonderful transparent and dynamic qualities of the current set-up. All stock power cords; haven't fooled around with that stuff. Can't imagine that would change the sound significantly. Any suggestions are welcome.