audiophiles who are just getting the itch to upgrade

Hello, I am reaching out to the community of those audiophiles who are looking at this unprecedented time in our history to upgrade their components. Why? because we are now spending so much more time with our gear and looking for ways to improve it, because we can :-) My questions is this; if there was one component you could upgrade in my system, what would it be and why?

• Linn Sonedek  LP 12 with Hercules board, Ittok II tonearm and Koetsu Black Cartridge
•  Fritz Carbon 7 SE Speakers - http://www.fritzspeakers.com/DreamWeaverFritzCarbon7Mk2SpecPage.asp
• Audio Mirror Tubadour III NOS DAC with   Miflex KPUC caps(courtesy of Don Sachs) and the Z foil resistors
• Cary Audio SL80- Signature 1 with VH audio Reference V-Cap CuTF output caps plus Cary volume IR upgrade and mains cap upgrades. Running Gold Lions KT88 matched tubes, Shuguang Treasure CV181Z - 6SN7 Pre-Driver/Phase Inverter tubes,  Sovtek NOS 6922 Input Buffer Preamp tubes and  WINGED "C" (SED) 5U4-G GREY PLATE tube
• Manley Labs Chinook phono pre-amp
  
• Cullen crossover series speaker cables and power cords

Well that's it and I know that are a lot of you in this community who have far more experience with matching systems and upgrades than I do. Thank you for your assistance and happy listening !