How to improve the sound of VTL2.5?

Any suggestion on how to improve the sound of VTL2.5? Especially on the high?
Sounds like a change of tubes, cables, powercords, or isolation support is the routes you have. What speciffically is bugging you and whats the rest of your system?
Try upscaleaudio for some better tubes
In addition to the usual suspects (see the two responses above), it may be something else, like your source. I recently purchased the GamuT CD-1 and was floored at all the new found music!
I just finished talking to VTL about possible improvements for my Vtl 2.5 and they (actually she) had a couple of ideas.

Since one of my tubes are really noisy, it was suggested to replace all 4 tubes ( 2 12au7s, and 2 6350s). Is it smart to change both sets of tubes at the same time? I don't know if the 12au7 and the 6350 have the same life span or not. They are about the same size, but obviously do different things. They also cost $15 each, which for currently manufactured tubes, seems to be a bit high.

The other option is to upgrade the caps on the preamp with, I believe, ?MIR? caps. This costs $200 and is suppose to really improve the overall sound. Does anyone have any experience with this type of upgrade? Does $200, parts and labor sound reasonable?